Right rail, top bar, bottom bar and chat border: Socials slide-out drawer, tab icons and colors, EDIT toggle, stream readouts moved to the top-left cell, webcam border restored, chat border controls, 30fps vertical tier

- Socials: the dialog is a right-rail drawer (same pattern as Stream Info/YPP/TEST); the live-screen button is removed
- Right rail: Stream Info (was Stream Settings) and YPP show the YouTube logo; Socials and TEST get icons; tab colors and label colors per spec
- Top bar: EDIT toggle beside REC (orange when on, blue when off); going live on YouTube turns it off
- Stream readouts (bitrate, FPS, dropped n (x.y%), Live hh:mm:ss, health) and the resolution dropdown moved to the top-left cell; bottom bar emptied at the same height
- Webcam border drawing restored (it was removed with the CRT bezel change)
- YouTube chat layer: border color, thickness, and opacity controls
- Vertical 1080p30 tier added

Not related to the fps gate yet; no gating is enforced.

.gitignore

@@ -1,12 +1,23 @@
 bin/
 obj/
 Helpers/OAuthCredentials.cs
+
+# Bundled FFmpeg (135 MB of DLLs). Fetched once by scripts/fetch-ffmpeg.sh, which pins
+# the URL + SHA-256; the build then copies it to the output. Never committed — see the
+# script header for why the hash, not the binaries, is the audit trail.
 *.user
 *.suo
 .vs/
 *.DotSettings.user
 
+# Build artifacts — the MSIX + its staging tree are produced by scripts/package-msix.sh,
+# never committed (the package embeds the published app and the bundled ffmpeg).
+artifacts/
+
 # Confidential business files (gitignored, not committed)
 MONETIZATION.md
 MARCOM.md
 CREDENTIALS.md
+.aider*
+ffmpeg/
+BuildCounter.txt

ADDITIONAL-TERMS.md

@@ -0,0 +1,54 @@
+# LlamaCasty — copyright, license, and additional terms
+
+Copyright (C) 2026 Gramps — https://llamacasty.com
+
+LlamaCasty is free software: you can redistribute it and/or modify it under the terms of the
+**GNU General Public License as published by the Free Software Foundation, either version 3 of
+the License, or (at your option) any later version** (GPL-3.0-or-later), together with the
+additional terms below, which section 7 of that license permits.
+The full license text is in [`LICENSE`](LICENSE).
+
+LlamaCasty is distributed in the hope that it will be useful, but **WITHOUT ANY WARRANTY**;
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+Third-party components bundled with LlamaCasty keep their own licenses — see
+[`THIRD-PARTY-NOTICES.txt`](THIRD-PARTY-NOTICES.txt).
+
+---
+
+## Additional terms (GPL-3.0 section 7)
+
+1. **Attribution — section 7(b).** Every conveyed copy of this program, modified or not, must keep
+   the copyright notice above and must show, in its About screen (or the equivalent place in its
+   user interface), the notice:
+
+   > Based on LlamaCasty by Gramps — https://llamacasty.com
+
+2. **Modified versions — section 7(c).** A modified version must be clearly marked as modified,
+   must use a name other than "LlamaCasty", and must not be represented as the original LlamaCasty
+   or as made or endorsed by Gramps.
+
+3. **Trademarks — section 7(e).** This license grants no right to use the LlamaCasty name, the
+   llama logo, or any other LlamaCasty brand mark, except for the factual attribution required by
+   term 1.
+
+## Brand artwork — not licensed under the GPL
+
+The following files are Copyright (C) 2026 Gramps, **all rights reserved**, and are **not**
+covered by GPL-3.0:
+
+- `Assets/llamacasty-icon.png`
+- `Assets/llamacasty-icon.ico`
+- `Assets/llamacasty-logo.jpg`
+
+Unmodified copies of LlamaCasty may be redistributed with these files included. Modified versions
+must replace them with their own artwork. No other use — including on merchandise — is permitted
+without written permission.
+
+## Placeholder artwork — licensed with the code
+
+The scene background images (`Assets/*-background.jpg`) and the default alert video
+(`Assets/alert-default.mp4`) are AI-generated placeholders, there so the app works the moment it
+opens. Creators are expected to replace them with their own. They are distributed with the code
+under GPL-3.0-or-later and carry none of the restrictions above.

AGENTS.md

@@ -20,6 +20,13 @@ work lands directly on `main`, committed and pushed per work unit. No
 `taskNN-*` branches, no PRs. The scope discipline above is about test focus,
 not git mechanics.
 
+**Commit / push policy (2026-08-30, user directive):** commit every work unit —
+committing is expected and never needs extra permission. Pushing is different:
+push ONLY at sub-milestones and milestones. During a multi-commit refactor,
+that means commits land locally every partial; `git push` happens at the
+session's agreed checkpoint(s), not per-commit. When a milestone warrants a
+push the user will say so (or say "push it").
+
 MUST read the architecture guide before planning or modifying the codebase:
 [`ai.md`](ai.md) (+ [`schema.md`](schema.md) for the memory-map conventions).
 
@@ -31,7 +38,7 @@ conventions live here and in `ai.md`.
 
 1. [`schema.md`](schema.md) — the memory-map conventions (what lives where, how to keep it true).
 2. [`ai.md`](ai.md) — the AI guide: architecture, patterns, decisions, current state.
-3. [`TASKS.md`](TASKS.md) — the task queue + authoritative YouTube API research.
+3. [`TASKS.md`](TASKS.md) — the task catalog (index + queue state); open items and API research facts are in [`TASKS/`](TASKS/).
 4. [`HANDOFF.md`](HANDOFF.md) — current operational state: what's in flight, landmines, next step.
 5. `<dir>/index.md` — the index for any directory you're about to touch.
 

App.xaml.cs

@@ -1,6 +1,5 @@
 using System.Windows;
 using System.Windows.Threading;
-using Velopack;
 using ytLive.Helpers;
 
 namespace ytLive;
@@ -26,20 +25,13 @@ public partial class App : Application
             AppLog.Write(args.Exception, "Dispatcher unhandled exception");
 
         AppLog.Write("App OnStartup begin");
+        // Attribution (2026-09-04): every take must be traceable to the exact binary
+        // that produced it — the wordmark shows the release counter (BuildStamp.Release);
+        // the per-build GUID is forensic only and lands here.
+        AppLog.Write($"Build {ytLive.Helpers.BuildStamp.Id} (compiled {ytLive.Helpers.BuildStamp.BuiltLocal})");
 
-        // Velopack auto-update bootstrap — checks for updates on startup and
-        // applies them (the app restarts automatically if an update is found).
-        // Update URL is configured per-deployment (self-hosted on DO droplet);
-        // when no URL is set, the check is a no-op.
-        try
-        {
-            VelopackApp.Build()
-                .Run();
-        }
-        catch (Exception ex)
-        {
-            AppLog.Write($"Velopack bootstrap failed (non-fatal): {ex.Message}");
-        }
+        // There is deliberately NO self-update bootstrap here: the Microsoft Store updates the
+        // app (TASK 48 — Store MSIX route), and a second updater would fight it.
 
         base.OnStartup(e);
         AppLog.Write("App OnStartup end");

Controls/BottomBar.xaml

@@ -0,0 +1,10 @@
+<UserControl x:Class="ytLive.Controls.BottomBar"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    <Border Background="#0f3460" Padding="16,4">
+        <Grid>
+            <!-- Intentionally empty. The hidden label keeps the bar's height unchanged. -->
+            <TextBlock Style="{StaticResource YtLabel}" Text=" " Visibility="Hidden"/>
+        </Grid>
+    </Border>
+</UserControl>

Controls/BottomBar.xaml.cs

@@ -0,0 +1,11 @@
+using System.Windows.Controls;
+
+namespace ytLive.Controls;
+
+public partial class BottomBar : UserControl
+{
+    public BottomBar()
+    {
+        InitializeComponent();
+    }
+}

Controls/HealthBanner.xaml

@@ -0,0 +1,12 @@
+<UserControl x:Class="ytLive.Controls.HealthBanner"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    <!-- YouTube health banner (TASK 5 item 3): report-by-exception — visible
+         ONLY while a warning/error configuration issue exists. Amber for
+         warning, darker red for error (HealthIssueBackground). -->
+    <Border Background="{Binding HealthIssueBackground}"
+            Visibility="{Binding HealthIssueBanner, Converter={StaticResource NotNullToVis}}">
+        <TextBlock Text="{Binding HealthIssueBanner}" Foreground="White" FontSize="13"
+                   FontWeight="SemiBold" Margin="16,8" TextTrimming="CharacterEllipsis"/>
+    </Border>
+</UserControl>

Controls/HealthBanner.xaml.cs

@@ -0,0 +1,11 @@
+using System.Windows.Controls;
+
+namespace ytLive.Controls;
+
+public partial class HealthBanner : UserControl
+{
+    public HealthBanner()
+    {
+        InitializeComponent();
+    }
+}

Controls/LeftPanel.xaml

@@ -0,0 +1,806 @@
+<UserControl x:Class="ytLive.Controls.LeftPanel"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:Helpers="clr-namespace:ytLive.Helpers"
+             xmlns:models="clr-namespace:ytLive.Models">
+    <UserControl.Resources>
+        <!-- TASK 63: the border-colour drop-down is the app's own YtComboBox, so the
+             colour entries are drawn by TEMPLATES, in the theme's colours and with the
+             theme's HexToBrush converter — no hand-built menu, no hand-painted brush.
+             The closed box shows the swatch + the colour's NAME; the rows show the
+             swatch + the hex + the name. -->
+        <DataTemplate x:Key="BorderColorClosedTemplate">
+            <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
+                <Border Width="12" Height="12" CornerRadius="2" VerticalAlignment="Center"
+                        Background="{Binding Hex, Converter={StaticResource HexToBrush}}"
+                        BorderBrush="#2a3a5e" BorderThickness="1"/>
+                <TextBlock Text="{Binding Name}" Margin="6,0,0,0" FontSize="12"
+                           Foreground="#e0e0e0" VerticalAlignment="Center"/>
+            </StackPanel>
+        </DataTemplate>
+        <DataTemplate x:Key="BorderColorRowTemplate">
+            <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
+                <Border Width="12" Height="12" CornerRadius="2" VerticalAlignment="Center"
+                        Background="{Binding Hex, Converter={StaticResource HexToBrush}}"
+                        BorderBrush="#2a3a5e" BorderThickness="1"/>
+                <TextBlock Text="{Binding Hex}" Margin="6,0,0,0" FontSize="12"
+                           Foreground="#e0e0e0" VerticalAlignment="Center"/>
+                <TextBlock Text="{Binding Name}" Margin="8,0,0,0" FontSize="12"
+                           Foreground="#a0a0b0" VerticalAlignment="Center"/>
+            </StackPanel>
+        </DataTemplate>
+        <Helpers:ClosedBoxTemplateSelector x:Key="BorderColorTemplates"
+                                           ClosedTemplate="{StaticResource BorderColorClosedTemplate}"
+                                           RowTemplate="{StaticResource BorderColorRowTemplate}"/>
+    </UserControl.Resources>
+
+    <Border Background="#16213e" CornerRadius="6" Padding="12">
+                <Grid>
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="*"/>
+                    </Grid.RowDefinitions>
+
+                    <!-- Edit mode (offline): layers + properties -->
+                    <Grid Grid.Row="0" Visibility="{Binding IsEditMode, Converter={StaticResource BoolToVis}}">
+                        <Grid.RowDefinitions>
+                            <RowDefinition Height="Auto"/>
+                            <RowDefinition Height="Auto"/>
+                            <RowDefinition Height="Auto"/>
+                            <RowDefinition Height="Auto"/>
+                            <RowDefinition Height="Auto"/>
+                            <RowDefinition Height="Auto"/>
+                            <RowDefinition Height="Auto"/>
+                        </Grid.RowDefinitions>
+
+                        <!-- LAYERS header + Add button -->
+                        <StackPanel Grid.Row="0" Orientation="Horizontal" Margin="0,8,0,0">
+                            <Path Data="M12,3 L21,8 L12,13 L3,8 Z M3,12 L12,17 L21,12 M3,16 L12,21 L21,16"
+                                  Stroke="#38bdf8" StrokeThickness="1.8" StrokeLineJoin="Round"
+                                  Width="16" Height="16" Stretch="Uniform" VerticalAlignment="Center" Margin="0,-4,6,0"/>
+                            <TextBlock Text="SCENE LAYERS" Style="{StaticResource SectionHeader}" VerticalAlignment="Center"/>
+                            <Border Width="20" Height="20" CornerRadius="10" Background="#334155" Margin="6,-4,0,0" VerticalAlignment="Center">
+                                <TextBlock Text="{Binding LayerCount}" Foreground="#38bdf8" FontSize="11" FontWeight="SemiBold"
+                                           HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                            </Border>
+                            <Button ToolTip="Add Layer" Style="{StaticResource IconButton}" Margin="4,-4,0,0"
+                                Click="AddSourceButton_Click">
+                            <Button.ContextMenu>
+                                <ContextMenu DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
+                                    <MenuItem Header="Webcam" Command="{Binding AddWebcamCommand}"
+                                              IsEnabled="{Binding CanAddWebcam}"
+                                              ToolTip="{Binding WebcamAddToolTip}"/>
+                                    <MenuItem Header="Image" Command="{Binding AddImageCommand}"/>
+                                    <MenuItem Header="Text" Command="{Binding AddSourceCommand}" CommandParameter="{x:Static models:SourceType.TextOverlay}"/>
+                                    <MenuItem Header="Countdown" Command="{Binding AddSourceCommand}" CommandParameter="{x:Static models:SourceType.Countdown}"
+                                              Visibility="{Binding IsCountdownAvailable, Converter={StaticResource BoolToVis}}"
+                                              ToolTip="Timer overlay — Starting and BRB screens only"/>
+                                    <MenuItem Header="Web Resource" Command="{Binding AddSourceCommand}" CommandParameter="{x:Static models:SourceType.WebSource}"
+                                              ToolTip="Embedded web page — set URI in Properties panel"/>
+                                    <MenuItem Header="YouTube Chat" Command="{Binding AddSourceCommand}" CommandParameter="{x:Static models:SourceType.ChatBox}"
+                                              IsEnabled="{Binding CanAddYouTubeChat}"
+                                              ToolTip="One chat layer at a time — it's already in your stream"/>
+                                    <MenuItem Header="Stream Alerts" Command="{Binding AddSourceCommand}" CommandParameter="{x:Static models:SourceType.AlertBox}"
+                                              IsEnabled="{Binding CanAddAlerts}"
+                                              ToolTip="Celebration zone for Super Chat &amp; memberships — one alert layer at a time"/>
+                                </ContextMenu>
+                            </Button.ContextMenu>
+                            <Path Data="M12,4 L12,20 M4,12 L20,12" Stroke="#e94560" StrokeThickness="2"
+                                  Width="14" Height="14" Stretch="Uniform"/>
+                        </Button>
+                    </StackPanel>
+
+                    <Helpers:FocusPreservingListBox x:Name="SourceList" Grid.Row="1" MinHeight="84" MaxHeight="240" Background="Transparent" BorderThickness="0"
+                             ItemsSource="{Binding StagedScene.Elements}"
+                             SelectedItem="{Binding SelectedElement, Mode=TwoWay}"
+                             PreviewMouseLeftButtonDown="List_PreviewMouseLeftButtonDown"
+                             PreviewMouseMove="List_PreviewMouseMove"
+                             PreviewMouseLeftButtonUp="List_PreviewMouseLeftButtonUp"
+                             Foreground="#e0e0e0" FontSize="13">
+                        <Helpers:FocusPreservingListBox.ItemContainerStyle>
+                            <Style TargetType="ListBoxItem" BasedOn="{StaticResource YtListBoxItem}">
+                                <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
+                                <Style.Triggers>
+                                    <DataTrigger Binding="{Binding IsVisible}" Value="False">
+                                        <Setter Property="Opacity" Value="0.45"/>
+                                    </DataTrigger>
+                                    <!-- The transient zoom layer has no editing UI — never
+                                         show it as a layer row (TASK 51). -->
+                                    <DataTrigger Binding="{Binding IsZoomLayer}" Value="True">
+                                        <Setter Property="Visibility" Value="Collapsed"/>
+                                    </DataTrigger>
+                                </Style.Triggers>
+                            </Style>
+                        </Helpers:FocusPreservingListBox.ItemContainerStyle>
+                        <ListBox.ItemTemplate>
+                            <DataTemplate>
+                                <Grid Margin="8,2,0,2"
+                                      Tag="{Binding DataContext.CanChangeBackground, RelativeSource={RelativeSource AncestorType=Window}}">
+                                    <Grid.ColumnDefinitions>
+                                        <ColumnDefinition Width="Auto"/>
+                                        <ColumnDefinition Width="*"/>
+                                        <ColumnDefinition Width="Auto"/>
+                                        <ColumnDefinition Width="Auto"/>
+                                        <ColumnDefinition Width="Auto"/>
+                                    </Grid.ColumnDefinitions>
+
+
+                                    <Grid.ContextMenu>
+                                        <ContextMenu DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
+                                            <MenuItem Header="Change Capture…" Click="BackgroundMenu_ChangeCapture">
+                                                <MenuItem.Visibility>
+                                                    <MultiBinding Converter="{StaticResource AllTrueToVis}">
+                                                        <Binding Path="IsBackground"/>
+                                                        <Binding Path="PlacementTarget.Tag" RelativeSource="{RelativeSource AncestorType={x:Type ContextMenu}}"/>
+                                                    </MultiBinding>
+                                                </MenuItem.Visibility>
+                                            </MenuItem>
+                                            <MenuItem Header="Refresh Capture" Click="BackgroundMenu_RefreshCapture">
+                                                <MenuItem.Visibility>
+                                                    <MultiBinding Converter="{StaticResource AllTrueToVis}">
+                                                        <Binding Path="IsBackground"/>
+                                                        <Binding Path="PlacementTarget.Tag" RelativeSource="{RelativeSource AncestorType={x:Type ContextMenu}}"/>
+                                                    </MultiBinding>
+                                                </MenuItem.Visibility>
+                                            </MenuItem>
+                                            <MenuItem Header="Capture Window…"
+                                                      ItemsSource="{Binding DataContext.OpenWindows, RelativeSource={RelativeSource AncestorType=Window}}">
+                                                <MenuItem.Visibility>
+                                                    <MultiBinding Converter="{StaticResource AllTrueToVis}">
+                                                        <Binding Path="IsBackground"/>
+                                                        <Binding Path="PlacementTarget.Tag" RelativeSource="{RelativeSource AncestorType={x:Type ContextMenu}}"/>
+                                                    </MultiBinding>
+                                                </MenuItem.Visibility>
+                                                <MenuItem.ItemContainerStyle>
+                                                    <Style TargetType="MenuItem">
+                                                        <Setter Property="Header" Value="{Binding Label}"/>
+                                                        <Setter Property="Command"
+                                                                Value="{Binding DataContext.CaptureWindowCommand, RelativeSource={RelativeSource AncestorType=Window}}"/>
+                                                        <Setter Property="CommandParameter" Value="{Binding}"/>
+                                                    </Style>
+                                                </MenuItem.ItemContainerStyle>
+                                            </MenuItem>
+                                            <MenuItem Header="Refresh Window List" Click="BackgroundMenu_RefreshWindowList">
+                                                <MenuItem.Visibility>
+                                                    <MultiBinding Converter="{StaticResource AllTrueToVis}">
+                                                        <Binding Path="IsBackground"/>
+                                                        <Binding Path="PlacementTarget.Tag" RelativeSource="{RelativeSource AncestorType={x:Type ContextMenu}}"/>
+                                                    </MultiBinding>
+                                                </MenuItem.Visibility>
+                                            </MenuItem>
+                                            <Separator>
+                                                <Separator.Visibility>
+                                                    <MultiBinding Converter="{StaticResource AllTrueToVis}">
+                                                        <Binding Path="IsBackground"/>
+                                                        <Binding Path="PlacementTarget.Tag" RelativeSource="{RelativeSource AncestorType={x:Type ContextMenu}}"/>
+                                                    </MultiBinding>
+                                                </Separator.Visibility>
+                                            </Separator>
+                                            <MenuItem Header="Remove Layer" Click="SourceMenu_Remove"
+                                                      Visibility="{Binding IsBackground, Converter={StaticResource InverseBoolToVis}}"/>
+                                        </ContextMenu>
+                                    </Grid.ContextMenu>
+
+                                    <Grid Grid.Column="0" Width="16" Height="16" Margin="0,0,6,0" VerticalAlignment="Center">
+                                        <Path Data="M7,8 H17 A4,4 0 0 1 21,12 V14 A3,3 0 0 1 17,16 L15,14 H9 L7,16 A3,3 0 0 1 3,14 V12 A4,4 0 0 1 7,8 Z M8,11 V13 M7,12 H9 M15,11 H15.01 M17,13 H17.01" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsLiveCapture}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M3,5 H21 V19 H3 Z M3,16 L9,10 L13,14 L16,11 L21,16" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><MultiDataTrigger><MultiDataTrigger.Conditions><Condition Binding="{Binding IsBackground}" Value="True"/><Condition Binding="{Binding IsLiveCapture}" Value="False"/></MultiDataTrigger.Conditions><Setter Property="Visibility" Value="Visible"/></MultiDataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M3,7 H15 V17 H3 Z M15,11 L21,8 V16 L15,13" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsWebcam}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M4,4 H20 V20 H4 Z M4,16 L9,11 L13,15 L16,12 L20,16 M15,8 H15.01" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsImageSource}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M5,5 H19 M12,5 V19 M8,19 H16" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsTextOverlay}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M12,3 A9,9 0 1 0 12.01,3 M12,7 V12 L15,14" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsCountdown}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M12,3 A9,9 0 1 0 12.01,3 M3,12 H21 M12,3 C8,7 8,17 12,21 M12,3 C16,7 16,17 12,21" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsWebSource}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M4,5 H20 V16 H10 L6,20 V16 H4 Z" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsChatBox}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M4,5 H20 V19 H4 Z M10,9 L15,12 L10,15 Z" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsMediaSource}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                        <Path Data="M6,16 V11 A6,6 0 0 1 18,11 V16 L20,18 H4 Z M10,20 H14" Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round" Stretch="Uniform">
+                                            <Path.Style><Style TargetType="Path"><Setter Property="Visibility" Value="Collapsed"/><Style.Triggers><DataTrigger Binding="{Binding IsAlertBox}" Value="True"><Setter Property="Visibility" Value="Visible"/></DataTrigger></Style.Triggers></Style></Path.Style>
+                                        </Path>
+                                    </Grid>
+
+                                    <TextBlock Grid.Column="1" Text="{Binding Name}" VerticalAlignment="Center"
+                                               Padding="4,2" TextTrimming="CharacterEllipsis">
+                                        <TextBlock.Style>
+                                            <Style TargetType="TextBlock">
+                                                <Setter Property="Visibility" Value="Visible"/>
+                                                <Style.Triggers>
+                                                    <DataTrigger Binding="{Binding IsEditing}" Value="True">
+                                                        <Setter Property="Visibility" Value="Collapsed"/>
+                                                    </DataTrigger>
+                                                </Style.Triggers>
+                                            </Style>
+                                        </TextBlock.Style>
+                                    </TextBlock>
+
+                                    <TextBox Grid.Column="1" Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}"
+                                             BorderThickness="0" FontSize="12"
+                                             IsVisibleChanged="SourceNameBox_IsVisibleChanged"
+                                             KeyDown="SourceNameBox_KeyDown" LostFocus="SourceNameBox_LostFocus">
+                                        <TextBox.Style>
+                                            <Style TargetType="TextBox" BasedOn="{StaticResource YtTextBoxCompact}">
+                                                <Setter Property="Visibility" Value="Collapsed"/>
+                                                <Style.Triggers>
+                                                    <DataTrigger Binding="{Binding IsEditing}" Value="True">
+                                                        <Setter Property="Visibility" Value="Visible"/>
+                                                    </DataTrigger>
+                                                </Style.Triggers>
+                                            </Style>
+                                        </TextBox.Style>
+                                    </TextBox>
+
+                                    <Button Grid.Column="2" ToolTip="Edit Layer Name"
+                                            Command="{Binding DataContext.EditElementCommand, RelativeSource={RelativeSource AncestorType=ListBox}}"
+                                            CommandParameter="{Binding}" Style="{StaticResource IconButton}">
+                                        <Path Data="M3,17.25V21h3.75L17.81,9.94l-3.75,-3.75L3,17.25zM20.71,7.04c0.39,-0.39 0.39,-1.02 0,-1.41l-2.34,-2.34c-0.39,-0.39 -1.02,-0.39 -1.41,0l-1.83,1.83 3.75,3.75 1.83,-1.83z"
+                                              Fill="#d0d0d0" Width="13" Height="13" Stretch="Uniform"/>
+                                    </Button>
+
+                                    <Button Grid.Column="3" Style="{StaticResource EyeButton}"
+                                            Command="{Binding DataContext.ToggleElementVisibilityCommand, RelativeSource={RelativeSource AncestorType=ListBox}}"
+                                            CommandParameter="{Binding}">
+                                        <Path Style="{StaticResource EyeIconStyle}" Fill="#d0d0d0"
+                                              Width="13" Height="13" Stretch="Uniform"/>
+                                    </Button>
+
+                                    <Button Grid.Column="4" ToolTip="Remove Layer"
+                                            Command="{Binding DataContext.RemoveSourceCommand, RelativeSource={RelativeSource AncestorType=ListBox}}"
+                                            CommandParameter="{Binding}" Style="{StaticResource IconButton}"
+                                            Visibility="{Binding IsBackground, Converter={StaticResource HiddenBoolToVis}}">
+                                        <Path Data="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2V7H6v12zM19,4h-3.5l-1,-1h-5l-1,1H5v2h14V4z"
+                                              Fill="#d0d0d0" Width="13" Height="13" Stretch="Uniform"/>
+                                    </Button>
+                                </Grid>
+                            </DataTemplate>
+                        </ListBox.ItemTemplate>
+                    </Helpers:FocusPreservingListBox>
+
+                            <TextBlock Grid.Row="2" Text="No layers yet" Foreground="#555" FontSize="12"
+                               HorizontalAlignment="Center" VerticalAlignment="Center"
+                               Visibility="{Binding ShowSourcesEmptyHint, Converter={StaticResource BoolToVis}}"/>
+
+                    <!-- Resource alert: pinned to the bottom of the Layers panel.
+                         Red when a required resource (the one-and-only webcam)
+                         could not be locked; persists and re-polls until resolved. -->
+                    <Border Grid.Row="3" Margin="0,8,0,0" Padding="8,6" CornerRadius="4"
+                            Background="#3a1216" BorderBrush="#e94560" BorderThickness="1"
+                            Visibility="{Binding WebcamLockAlert, Converter={StaticResource NotNullToVis}}">
+                        <StackPanel>
+                            <TextBlock Text="{Binding WebcamLockAlert}" Foreground="#ffb4b4" FontSize="11"
+                                       TextWrapping="Wrap"/>
+                            <Button Content="Retry" Command="{Binding RetryWebcamLockCommand}"
+                                    Style="{StaticResource YtButtonSecondary}" Padding="10,2"
+                                    HorizontalAlignment="Right" Margin="0,6,0,0"/>
+                        </StackPanel>
+                    </Border>
+
+                    <!-- ELEMENTS panel: per-element config beneath Sources.
+                         Collapses entirely when no element is selected. -->
+                    <Rectangle Grid.Row="4" Height="1" Fill="#2c3a5c" Margin="0,22,0,10"/>
+                    <StackPanel Grid.Row="5" Orientation="Horizontal" Margin="0,8,0,0">
+                        <Path Data="M12,8 A4,4 0 1 0 12.01,8 M19.4,15 L21,16.2 L19.4,19 L17.2,18.3 A7,7 0 0 1 15,19.4 L14.5,21.5 H9.5 L9,19.4 A7,7 0 0 1 6.8,18.3 L4.6,19 L3,16.2 L4.6,15 A7,7 0 0 1 4.6,9 L3,7.8 L4.6,5 L6.8,5.7 A7,7 0 0 1 9,4.6 L9.5,2.5 H14.5 L15,4.6 A7,7 0 0 1 17.2,5.7 L19.4,5 L21,7.8 L19.4,9 A7,7 0 0 1 19.4,15 Z"
+                              Stroke="#38bdf8" StrokeThickness="1.6" StrokeLineJoin="Round"
+                              Width="16" Height="16" Stretch="Uniform" VerticalAlignment="Center" Margin="0,0,6,0"/>
+                        <TextBlock Text="PROPERTIES" Style="{StaticResource SectionHeader}" VerticalAlignment="Center"/>
+                    </StackPanel>
+                    <TextBlock Grid.Row="6" Text="Select an item to edit its properties" Foreground="#94a3b8" FontSize="12"
+                               Margin="8,4,0,0" TextWrapping="Wrap"
+                               Visibility="{Binding SelectedElement, Converter={StaticResource NullToVis}}"/>
+                    <ScrollViewer x:Name="ElementsScrollViewer" Grid.Row="6" MaxHeight="420" VerticalScrollBarVisibility="Auto" Background="Transparent"
+                                  Visibility="{Binding SelectedElement, Converter={StaticResource NotNullToVis}}">
+                        <StackPanel x:Name="ElementsPanel" Margin="8,4,0,0">
+                            <!-- Opacity + mirror/shape (draggable elements: image, webcam) -->
+                            <StackPanel Visibility="{Binding SelectedElement.IsDraggable, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <StackPanel Visibility="{Binding SelectedElement.IsChatBox, Converter={StaticResource InverseBoolToVis}}">
+                                    <TextBlock Text="Opacity" Foreground="#a0a0b0" FontSize="11" Margin="0,0,0,2"/>
+                                    <DockPanel Margin="0,0,0,6">
+                                        <TextBlock x:Name="OpacityValueText" Text="100%" Foreground="#a0a0b0" FontSize="11"
+                                                   DockPanel.Dock="Right" VerticalAlignment="Center" Margin="8,0,0,0" Width="32"/>
+                                        <Slider x:Name="OpacitySlider" Width="120" Minimum="0" Maximum="1"
+                                                Value="{Binding SelectedElement.Opacity, Mode=TwoWay}"
+                                                ValueChanged="OpacitySlider_ValueChanged" VerticalAlignment="Center"/>
+                                    </DockPanel>
+                                </StackPanel>
+                                <!-- TASK 59: the shape is a CHOICE (Rect | Circle) under a
+                                     "Shape" title, with Rect selected by default — the circle
+                                     is not offered in the vertical Chat layout, so that option
+                                     is not even shown there (CanToggleClipShape). -->
+                                <StackPanel Visibility="{Binding IsWebcamSelected, Converter={StaticResource BoolToVis}}">
+                                    <TextBlock Text="Shape" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,4"/>
+                                    <StackPanel Orientation="Horizontal" Margin="10,0,0,4">
+                                        <Button Content="{Binding SelectedElement.MirrorButtonText}"
+                                                Style="{StaticResource YtButtonSecondary}" Padding="10,4"
+                                                Click="MirrorButton_Click"/>
+                                        <ToggleButton Style="{StaticResource SegmentToggle}" Padding="10,4" Margin="8,0,0,0"
+                                                      IsChecked="{Binding SelectedElement.IsRectShape, Mode=TwoWay}">
+                                            <TextBlock Text="Rect" Style="{StaticResource SegmentLabel}"/>
+                                        </ToggleButton>
+                                        <ToggleButton Style="{StaticResource SegmentToggle}" Padding="10,4" Margin="4,0,0,0"
+                                                      IsChecked="{Binding SelectedElement.IsRoundShape, Mode=TwoWay}"
+                                                      Visibility="{Binding CanToggleClipShape, Converter={StaticResource BoolToVis}}">
+                                            <TextBlock Text="Circle" Style="{StaticResource SegmentLabel}"/>
+                                        </ToggleButton>
+                                    </StackPanel>
+                                </StackPanel>
+                                <!-- The drag hint sits under the shape row — indented, so the
+                                     parentage shows. -->
+                                <TextBlock Text="Drag to move · drag the corner dot to resize"
+                                           Foreground="#a0a0b0" FontSize="10" Margin="10,2,0,0"/>
+                            </StackPanel>
+
+                            <!-- Webcam geometry (TASK 57): under the vertical tier the camera
+                                 keeps its OWN placement, so these fields edit the LIVE one —
+                                 the placement the current tier shows. Gated on the VM's
+                                 IsWebcamSelected (the same condition as the mirror/shape row
+                                 above) so the webcam's border/background section stays the
+                                 one panel bound to SelectedElement.IsWebcam. -->
+                            <StackPanel Visibility="{Binding IsWebcamSelected, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <TextBlock Text="Geometry" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,8,0,4"/>
+                                <!-- TASK 61: the four fields share ONE fixed width — wide enough
+                                     for the largest geometry value (1920, plus a typed sign) and
+                                     no wider, so Y/H no longer stretch to fill the row. -->
+                                <DockPanel Margin="10,0,0,4" LastChildFill="False">
+                                    <TextBlock DockPanel.Dock="Left" Text="X" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="16"/>
+                                    <TextBox Text="{Binding SelectedElement.X, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="44"/>
+                                    <TextBlock DockPanel.Dock="Left" Text="  Y" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="20" Margin="8,0,0,0"/>
+                                    <TextBox Text="{Binding SelectedElement.Y, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="44"/>
+                                </DockPanel>
+                                <DockPanel Margin="10,0,0,4" LastChildFill="False">
+                                    <TextBlock DockPanel.Dock="Left" Text="W" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="16"/>
+                                    <TextBox Text="{Binding SelectedElement.Width, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="44"/>
+                                    <TextBlock DockPanel.Dock="Left" Text="  H" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="20" Margin="8,0,0,0"/>
+                                    <TextBox Text="{Binding SelectedElement.Height, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="44"/>
+                                </DockPanel>
+                            </StackPanel>
+
+                            <!-- Webcam border config -->
+                            <StackPanel Visibility="{Binding SelectedElement.IsWebcam, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <TextBlock Text="Border Color" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,8,0,2"/>
+                                <!-- TASK 63: the border colour is picked with the app's OWN
+                                     drop-down (YtComboBox) — the same widget the Display
+                                     and Font pickers use — not a hand-rolled menu. The hex
+                                     field stays for a colour the creator types; the
+                                     drop-down carries the colour's name. -->
+                                <DockPanel Margin="10,0,0,6">
+                                    <TextBox DockPanel.Dock="Left"
+                                             Text="{Binding SelectedElement.BorderColor, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}"
+                                             MaxLength="7" ToolTip="#RRGGBB" Width="60"
+                                             VerticalAlignment="Center"/>
+                                    <ComboBox ItemsSource="{Binding SelectedElement.BorderColorOptions}"
+                                              SelectedItem="{Binding SelectedElement.BorderColorEntry, Mode=TwoWay}"
+                                              ItemTemplateSelector="{StaticResource BorderColorTemplates}"
+                                              Style="{StaticResource YtComboBox}"
+                                              ToolTip="Border colour" MinWidth="100"
+                                              Margin="8,0,0,0" VerticalAlignment="Center"/>
+                                </DockPanel>
+                                <TextBlock Text="Border Thickness" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,8,0,2"/>
+                                <DockPanel Margin="10,0,0,6">
+                                    <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
+                                            Width="22" Height="22" Margin="4,0,0,0"
+                                            Click="WebcamBorderAccept_Click">
+                                        <Path Data="M4,9 L8,14 L16,4" Stroke="#22c55e" StrokeThickness="2"
+                                              Width="14" Height="14" Stretch="Uniform"/>
+                                    </Button>
+                                    <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
+                                            Width="22" Height="22" ToolTip="Revert"
+                                            Click="WebcamBorderRevert_Click" Margin="4,0,0,0">
+                                        <Path Data="M5,5 L15,15 M15,5 L5,15" Stroke="#e94560" StrokeThickness="2"
+                                              Width="14" Height="14" Stretch="Uniform"/>
+                                    </Button>
+                                    <Slider DockPanel.Dock="Left" Width="120" Minimum="0" Maximum="10"
+                                            Value="{Binding SelectedElement.BorderWidth, Mode=TwoWay}"
+                                            VerticalAlignment="Center" TickFrequency="1" IsSnapToTickEnabled="True"/>
+                                    <TextBlock Text="{Binding SelectedElement.BorderWidth}" Foreground="#a0a0b0" FontSize="11"
+                                               VerticalAlignment="Center" Margin="8,0,0,0" Width="20"/>
+                                </DockPanel>
+
+                                <!-- TASK 51: background effects — two pills acting as radio buttons
+                                     (one on turns the other off; both off = no effect). TASK 59:
+                                     the pills are indented under the Background title, and the
+                                     strength row one level deeper, under Blur. -->
+                                <TextBlock Text="Background" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,8,0,6"/>
+                                <DockPanel Margin="10,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Remove" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <ToggleButton x:Name="RemoveBackgroundPill" Style="{StaticResource PillToggle}"
+                                                  IsChecked="{Binding SelectedElement.RemoveBackground, Mode=TwoWay}"
+                                                  AutomationProperties.Name="Remove background"
+                                                  ToolTip="Remove the background behind you — the layers below show through"
+                                                  HorizontalAlignment="Left"/>
+                                </DockPanel>
+                                <DockPanel Margin="10,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Blur" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <ToggleButton x:Name="BlurBackgroundPill" Style="{StaticResource PillToggle}"
+                                                  IsChecked="{Binding SelectedElement.BlurBackground, Mode=TwoWay}"
+                                                  AutomationProperties.Name="Blur background"
+                                                  ToolTip="Blur the background behind you"
+                                                  HorizontalAlignment="Left"/>
+                                </DockPanel>
+                                <DockPanel Margin="20,0,0,6"
+                                           Visibility="{Binding SelectedElement.HasBackgroundEffect, Converter={StaticResource BoolToVis}}">
+                                    <TextBlock DockPanel.Dock="Left" Text="Strength" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <TextBlock DockPanel.Dock="Right" Text="{Binding SelectedElement.BackgroundStrength, StringFormat={}{0:P0}}"
+                                               Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Margin="8,0,0,0" Width="34"/>
+                                    <Slider x:Name="BackgroundStrengthSlider" Minimum="0" Maximum="1"
+                                            Value="{Binding SelectedElement.BackgroundStrength, Mode=TwoWay}"
+                                            TickFrequency="0.05" IsSnapToTickEnabled="True" VerticalAlignment="Center"
+                                            AutomationProperties.Name="Background effect strength"
+                                            ToolTip="Blur: how strong the blur is · Remove: how soft the edge is"/>
+                                </DockPanel>
+                            </StackPanel>
+
+                            <!-- Countdown config -->
+                            <StackPanel Visibility="{Binding SelectedElement.IsCountdown, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <TextBlock Text="Timer (minutes)" Foreground="#a0a0b0" FontSize="11" Margin="0,0,0,2"/>
+                                <DockPanel Margin="0,0,0,6">
+                                    <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
+                                            Width="22" Height="22" Margin="4,0,0,0"
+                                            Click="CountdownAccept_Click">
+                                        <Path Data="M4,9 L8,14 L16,4" Stroke="#22c55e" StrokeThickness="2"
+                                              Width="14" Height="14" Stretch="Uniform"/>
+                                    </Button>
+                                    <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
+                                            Width="22" Height="22" ToolTip="Revert"
+                                            Click="CountdownRevert_Click" Margin="4,0,0,0">
+                                        <Path Data="M5,5 L15,15 M15,5 L5,15" Stroke="#e94560" StrokeThickness="2"
+                                              Width="14" Height="14" Stretch="Uniform"/>
+                                    </Button>
+                                    <Slider DockPanel.Dock="Left" Width="120" Minimum="1" Maximum="60"
+                                            Value="{Binding SelectedElement.TimerMinutes, Mode=TwoWay}"
+                                            VerticalAlignment="Center" TickFrequency="1" IsSnapToTickEnabled="True"/>
+                                    <TextBlock Text="{Binding SelectedElement.TimerMinutes}" Foreground="#a0a0b0" FontSize="11"
+                                               VerticalAlignment="Center" Margin="8,0,0,0" Width="20"/>
+                                </DockPanel>
+                            </StackPanel>
+
+                            <!-- Web source config -->
+                            <StackPanel Visibility="{Binding SelectedElement.IsWebSource, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <TextBlock Text="Geometry" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,4"/>
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="X" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="16"/>
+                                    <TextBox Text="{Binding SelectedElement.X, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}"/>
+                                    <TextBlock DockPanel.Dock="Left" Text="  Y" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="20" Margin="8,0,0,0"/>
+                                    <TextBox Text="{Binding SelectedElement.Y, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}"/>
+                                </DockPanel>
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="W" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="16"/>
+                                    <TextBox Text="{Binding SelectedElement.Width, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}"/>
+                                    <TextBlock DockPanel.Dock="Left" Text="  H" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="20" Margin="8,0,0,0"/>
+                                    <TextBox Text="{Binding SelectedElement.Height, UpdateSourceTrigger=PropertyChanged, StringFormat=F0}"
+                                             Style="{StaticResource YtTextBoxCompact}"/>
+                                </DockPanel>
+                                <TextBlock Text="URI" Foreground="#a0a0b0" FontSize="11" Margin="0,0,0,2"/>
+                                <DockPanel>
+                                    <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
+                                            Width="22" Height="22" Margin="4,0,0,0" IsTabStop="False"
+                                            Click="WebAccept_Click">
+                                        <Path Data="M4,9 L8,14 L16,4" Stroke="#22c55e" StrokeThickness="2"
+                                              Width="14" Height="14" Stretch="Uniform"/>
+                                    </Button>
+                                    <Button DockPanel.Dock="Right" Style="{StaticResource IconButton}"
+                                            Width="22" Height="22" ToolTip="Revert" IsTabStop="False"
+                                            Click="WebRevert_Click" Margin="4,0,0,0">
+                                        <Path Data="M5,5 L15,15 M15,5 L5,15" Stroke="#e94560" StrokeThickness="2"
+                                              Width="14" Height="14" Stretch="Uniform"/>
+                                    </Button>
+                                    <TextBox Text="{Binding SelectedElement.WebUri, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}"
+                                             ToolTip="https://example.com"/>
+                                </DockPanel>
+                            </StackPanel>
+
+                            <!-- Chat box config -->
+                            <StackPanel Visibility="{Binding SelectedElement.IsChatBox, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <TextBlock Text="Chat Overlay" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,6"/>
+
+                                <!-- Border (same controls as the webcam's border) -->
+                                <TextBlock Text="Border Color" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,2"/>
+                                <DockPanel Margin="10,0,0,6">
+                                    <TextBox DockPanel.Dock="Left"
+                                             Text="{Binding SelectedElement.BorderColor, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}"
+                                             MaxLength="7" ToolTip="#RRGGBB" Width="60"
+                                             VerticalAlignment="Center"/>
+                                    <ComboBox ItemsSource="{Binding SelectedElement.BorderColorOptions}"
+                                              SelectedItem="{Binding SelectedElement.BorderColorEntry, Mode=TwoWay}"
+                                              ItemTemplateSelector="{StaticResource BorderColorTemplates}"
+                                              Style="{StaticResource YtComboBox}"
+                                              ToolTip="Border colour" MinWidth="100"
+                                              Margin="8,0,0,0" VerticalAlignment="Center"/>
+                                </DockPanel>
+                                <TextBlock Text="Border Thickness" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,2"/>
+                                <DockPanel Margin="10,0,0,6">
+                                    <Slider DockPanel.Dock="Left" Width="120" Minimum="0" Maximum="10"
+                                            Value="{Binding SelectedElement.BorderWidth, Mode=TwoWay}"
+                                            VerticalAlignment="Center" TickFrequency="1" IsSnapToTickEnabled="True"/>
+                                    <TextBlock Text="{Binding SelectedElement.BorderWidth}" Foreground="#a0a0b0" FontSize="11"
+                                               VerticalAlignment="Center" Margin="8,0,0,0" Width="20"/>
+                                </DockPanel>
+                                <TextBlock Text="Border Opacity" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,2"/>
+                                <DockPanel Margin="10,0,0,8">
+                                    <Slider DockPanel.Dock="Left" Width="120" Minimum="0" Maximum="1"
+                                            Value="{Binding SelectedElement.BorderOpacity, Mode=TwoWay}"
+                                            VerticalAlignment="Center"/>
+                                    <TextBlock Text="{Binding SelectedElement.BorderOpacity, StringFormat={}{0:P0}}" Foreground="#a0a0b0" FontSize="11"
+                                               VerticalAlignment="Center" Margin="8,0,0,0" Width="34"/>
+                                </DockPanel>
+
+                                <!-- Font Size -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Font Size" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <Slider x:Name="ChatFontSizeSlider" Width="120" Minimum="8" Maximum="72" TickFrequency="2" IsSnapToTickEnabled="True"
+                                            Value="{Binding SelectedElement.ChatFontSize, Mode=TwoWay}"
+                                            VerticalAlignment="Center"/>
+                                    <TextBlock DockPanel.Dock="Right" Text="{Binding SelectedElement.ChatFontSize, StringFormat={}{0:0}}" Foreground="#e0e0e0" FontSize="11" Margin="6,0,0,0" VerticalAlignment="Center" Width="24"/>
+                                </DockPanel>
+
+                                <!-- Font Family -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Font" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <ComboBox SelectedValue="{Binding SelectedElement.ChatFontFamily, Mode=TwoWay}"
+                                              SelectedValuePath="Content"
+                                              Style="{StaticResource YtComboBox}"
+                                              Width="140" VerticalAlignment="Center">
+                                        <ComboBoxItem Content="Segoe UI"/>
+                                        <ComboBoxItem Content="Arial"/>
+                                        <ComboBoxItem Content="Consolas"/>
+                                        <ComboBoxItem Content="Courier New"/>
+                                        <ComboBoxItem Content="Comic Sans MS"/>
+                                        <ComboBoxItem Content="Mouse Memoirs"/>
+                                    </ComboBox>
+                                </DockPanel>
+
+                                <!-- Font Color -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Font Color" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <TextBox Text="{Binding SelectedElement.ChatFontColor, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="80"/>
+                                </DockPanel>
+
+                                <!-- Member Color -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Member" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <TextBox Text="{Binding SelectedElement.ChatMemberColor, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="80"/>
+                                </DockPanel>
+
+                                <!-- Super Chat Color -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Super Chat" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <TextBox Text="{Binding SelectedElement.ChatSuperChatColor, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="80"/>
+                                </DockPanel>
+
+                                <!-- Max Messages -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Max Msgs" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <Slider x:Name="ChatMaxMsgsSlider" Width="120" Minimum="1" Maximum="20" TickFrequency="1" IsSnapToTickEnabled="True"
+                                            Value="{Binding SelectedElement.ChatMaxMessages, Mode=TwoWay}"
+                                            VerticalAlignment="Center"/>
+                                    <TextBlock DockPanel.Dock="Right" Text="{Binding SelectedElement.ChatMaxMessages}" Foreground="#e0e0e0" FontSize="11" Margin="6,0,0,0" VerticalAlignment="Center" Width="24"/>
+                                </DockPanel>
+
+                                <!-- Background Color -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Background" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <TextBox Text="{Binding SelectedElement.ChatBackgroundColor, UpdateSourceTrigger=PropertyChanged}"
+                                             Style="{StaticResource YtTextBoxCompact}" Width="80"/>
+                                </DockPanel>
+
+                                <!-- Background Opacity -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Bg Opacity" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <Slider x:Name="ChatBgOpacitySlider" Width="120" Minimum="0" Maximum="1"
+                                            Value="{Binding SelectedElement.ChatBackgroundOpacity, Mode=TwoWay}"
+                                            VerticalAlignment="Center"/>
+                                    <TextBlock DockPanel.Dock="Right" Text="{Binding SelectedElement.ChatBackgroundOpacity, StringFormat={}{0:0%}}" Foreground="#e0e0e0" FontSize="11" Margin="6,0,0,0" VerticalAlignment="Center" Width="32"/>
+                                </DockPanel>
+
+                                <!-- Fade After (seconds) -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Fade After" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="70"/>
+                                    <Slider x:Name="ChatFadeSlider" Width="120" Minimum="0" Maximum="60" TickFrequency="5" IsSnapToTickEnabled="True"
+                                            Value="{Binding SelectedElement.ChatFadeSeconds, Mode=TwoWay}"
+                                            VerticalAlignment="Center"/>
+                                    <TextBlock DockPanel.Dock="Right" Text="{Binding SelectedElement.ChatFadeSeconds, StringFormat='{}{0}s'}" Foreground="#e0e0e0" FontSize="11" Margin="6,0,0,0" VerticalAlignment="Center" Width="28"/>
+                                </DockPanel>
+
+                                <!-- Toggles -->
+                                <CheckBox Content="Show timestamps" Style="{StaticResource YtCheckBox}" Margin="0,4,0,2"
+                                          IsChecked="{Binding SelectedElement.ChatShowTimestamps, Mode=TwoWay}"/>
+                                <CheckBox Content="Show badges" Style="{StaticResource YtCheckBox}" Margin="0,0,0,2"
+                                          IsChecked="{Binding SelectedElement.ChatShowBadges, Mode=TwoWay}"/>
+                            </StackPanel>
+
+                            <!-- Stream Alerts config -->
+                            <StackPanel Visibility="{Binding SelectedElement.IsAlertBox, Converter={StaticResource BoolToVis}}" Margin="0,0,0,8">
+                                <TextBlock Text="Stream Alerts" Foreground="#a0a0b0" FontSize="11" FontWeight="SemiBold" Margin="0,0,0,6"/>
+                                <TextBlock Text="The built-in clip plays on every alert (Super Chat, membership…) unless a custom video is picked."
+                                           Foreground="#888" FontSize="10" TextWrapping="Wrap" Margin="0,0,0,6"/>
+
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Built-in video" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <ToggleButton Style="{StaticResource PillToggle}"
+                                                  IsChecked="{Binding SelectedElement.AlertUseDefaultVideo, Mode=TwoWay}"
+                                                  HorizontalAlignment="Left"/>
+                                </DockPanel>
+
+                                <Grid Margin="0,0,0,4"
+                                      Visibility="{Binding SelectedElement.AlertUseDefaultVideo, Converter={StaticResource InverseBoolToVis}}">
+                                    <Grid.ColumnDefinitions>
+                                        <ColumnDefinition Width="*"/>
+                                        <ColumnDefinition Width="Auto"/>
+                                    </Grid.ColumnDefinitions>
+                                    <TextBox Grid.Column="0" Text="{Binding SelectedElement.AlertVideoPath, Mode=OneWay}"
+                                             Style="{StaticResource YtTextBoxCompact}"
+                                             IsReadOnly="True" Foreground="#a0a0b0" VerticalAlignment="Center"/>
+                                    <Button Grid.Column="1" Content="Browse…" Command="{Binding BrowseAlertVideoCommand}"
+                                            CommandParameter="{Binding SelectedElement}" Style="{StaticResource YtButtonSecondary}"
+                                            Margin="4,0,0,0" Padding="8,2"/>
+                                </Grid>
+
+                                <Button Content="Reset to built-in" Command="{Binding ResetAlertVideoCommand}"
+                                        CommandParameter="{Binding SelectedElement}" Style="{StaticResource YtButtonSecondary}"
+                                        HorizontalAlignment="Left" Padding="8,2" Margin="0,0,4,0"/>
+                                <TextBlock Text="Custom clips are referenced from disk — never stored in the layout."
+                                           Foreground="#888" FontSize="10" TextWrapping="Wrap" Margin="0,4,0,6"/>
+
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Message ticker" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <ToggleButton Style="{StaticResource PillToggle}"
+                                                  IsChecked="{Binding SelectedElement.AlertShowTicker, Mode=TwoWay}"
+                                                  HorizontalAlignment="Left"/>
+                                </DockPanel>
+
+                                <!-- Announcement display: scroll (marquee), flash (pulse) or
+                                     solid (still). Inline items, not a bound ItemsSource —
+                                     same shape as the chat Font selector above. -->
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Display" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <ComboBox SelectedValue="{Binding SelectedElement.AlertDisplayMethod, Mode=TwoWay}"
+                                              SelectedValuePath="Tag"
+                                              Style="{StaticResource YtComboBox}"
+                                              Width="140" VerticalAlignment="Center">
+                                        <ComboBoxItem Content="Scroll" Tag="TickerScroll"/>
+                                        <ComboBoxItem Content="Flash" Tag="Flash"/>
+                                        <ComboBoxItem Content="Solid" Tag="Solid"/>
+                                    </ComboBox>
+                                </DockPanel>
+
+                                <DockPanel Margin="0,0,0,4">
+                                    <TextBlock DockPanel.Dock="Left" Text="Volume" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center" Width="84"/>
+                                    <Slider Width="120" Minimum="0" Maximum="1"
+                                            Value="{Binding SelectedElement.AlertVideoVolume, Mode=TwoWay}"
+                                            VerticalAlignment="Center"/>
+                                    <TextBlock DockPanel.Dock="Right" Text="{Binding SelectedElement.AlertVideoVolume, StringFormat={}{0:0%}}" Foreground="#e0e0e0" FontSize="11" Margin="6,0,0,0" VerticalAlignment="Center" Width="32"/>
+                                </DockPanel>
+                            </StackPanel>
+
+                            <!-- Background properties -->
+                            <StackPanel Margin="0,8,0,0"
+                                        Visibility="{Binding SelectedElement.IsBackground, Converter={StaticResource BoolToVis}}">
+                                <TextBlock Text="Background" Style="{StaticResource SubHeader}"/>
+                                <StackPanel Margin="4,0,0,0">
+                                    <StackPanel Orientation="Horizontal" Margin="0,0,0,8">
+                                        <TextBlock Text="Use default background:" Foreground="#a0a0b0" FontSize="11" VerticalAlignment="Center"/>
+                                        <ToggleButton Style="{StaticResource PillToggle}"
+                                                      IsChecked="{Binding SelectedElement.UseDefaultBackground, Mode=TwoWay}"
+                                                      Margin="8,0,0,0"/>
+                                    </StackPanel>
+                                    <Grid Margin="0,0,0,4"
+                                          Visibility="{Binding SelectedElement.UseDefaultBackground, Converter={StaticResource InverseBoolToVis}}">
+                                        <Grid.ColumnDefinitions>
+                                            <ColumnDefinition Width="*"/>
+                                            <ColumnDefinition Width="Auto"/>
+                                        </Grid.ColumnDefinitions>
+                                        <TextBox Grid.Column="0" Text="{Binding SelectedElement.CustomBackgroundPath, Mode=OneWay}"
+                                                  Style="{StaticResource YtTextBoxCompact}"
+                                                  IsReadOnly="True" Foreground="#a0a0b0" VerticalAlignment="Center"/>
+                                        <Button Grid.Column="1" Content="Browse…" Command="{Binding BrowseBackgroundCommand}"
+                                                Style="{StaticResource YtButtonSecondary}" Margin="4,0,0,0" Padding="8,2"/>
+                                    </Grid>
+                                    <TextBlock Text="{Binding BackgroundSizeMismatchText}"
+                                               Foreground="#ef4444" FontSize="11" TextWrapping="Wrap"
+                                               Margin="0,4,0,0"
+                                               Visibility="{Binding BackgroundSizeMismatch, Converter={StaticResource BoolToVis}}"/>
+                                </StackPanel>
+                            </StackPanel>
+                        </StackPanel>
+                    </ScrollViewer>
+                </Grid>
+
+                <!-- Live mode: YouTube Live Chat (entire left panel replaced) -->
+                <Grid Grid.Row="0" Visibility="{Binding IsEditMode, Converter={StaticResource InverseBoolToVis}}">
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto"/>
+                        <RowDefinition Height="*"/>
+                    </Grid.RowDefinitions>
+
+                    <TextBlock Grid.Row="0" Text="LIVE CHAT" Style="{StaticResource SectionHeader}"/>
+
+                    <!-- Inactive overlay (shown when NOT live) -->
+                    <StackPanel Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Center"
+                                Visibility="{Binding ShowChatInactiveMessage, Converter={StaticResource BoolToVis}}">
+                        <TextBlock Text="Chat is inactive" Foreground="#a0a0b0" FontSize="13"
+                                   HorizontalAlignment="Center" Margin="0,0,0,4"/>
+                        <TextBlock Text="Chat becomes active once LlamaCasty is connected and streaming on YouTube."
+                                   Foreground="#666" FontSize="11" TextWrapping="Wrap"
+                                   HorizontalAlignment="Center" TextAlignment="Center" MaxWidth="240"/>
+                    </StackPanel>
+
+                    <!-- Pinned message -->
+                    <Border Grid.Row="1" VerticalAlignment="Top" Margin="4,4,4,0" Padding="6,4" CornerRadius="4"
+                            Background="#1a2a3a" BorderBrush="#38bdf8" BorderThickness="1"
+                            Visibility="{Binding PinnedChatMessage, Converter={StaticResource NotNullToVis}}">
+                        <StackPanel>
+                            <TextBlock Text="{Binding PinnedChatMessage.AuthorName}" Foreground="#38bdf8" FontWeight="SemiBold" FontSize="11"/>
+                            <TextBlock Text="{Binding PinnedChatMessage.Message}" Foreground="#e0e0e0" FontSize="11" TextWrapping="Wrap"/>
+                        </StackPanel>
+                    </Border>
+
+                    <!-- Message feed (shown when live) -->
+                    <ListBox Grid.Row="1" Background="Transparent" BorderThickness="0" Margin="0,40,0,0"
+                             ItemsSource="{Binding ChatMessages}"
+                             ItemContainerStyle="{StaticResource YtListBoxItem}"
+                             Visibility="{Binding ShowChatInactiveMessage, Converter={StaticResource InverseBoolToVis}}"
+                             x:Name="ChatListBox">
+                        <ListBox.ItemTemplate><DataTemplate>
+                            <Border x:Name="MessageBorder" Padding="6,4" CornerRadius="4">
+                                <Border.Style>
+                                    <Style TargetType="Border">
+                                        <Setter Property="Background" Value="Transparent"/>
+                                        <Style.Triggers>
+                                            <DataTrigger Binding="{Binding IsSuperChat}" Value="True">
+                                                <Setter Property="Background" Value="#2a1a0a"/>
+                                                <Setter Property="BorderBrush" Value="#eab308"/>
+                                                <Setter Property="BorderThickness" Value="1,0,1,0"/>
+                                            </DataTrigger>
+                                        </Style.Triggers>
+                                    </Style>
+                                </Border.Style>
+                                <StackPanel>
+                                    <StackPanel Orientation="Horizontal" Margin="0,0,0,2">
+                                        <TextBlock Text="&#x2B50;" FontSize="10" Margin="0,0,4,0"
+                                                   VerticalAlignment="Center"
+                                                   Visibility="{Binding IsMember, Converter={StaticResource BoolToVis}}"/>
+                                        <TextBlock Text="{Binding AuthorName}" Foreground="#e94560"
+                                                   FontWeight="Bold" FontSize="12" VerticalAlignment="Center"/>
+                                        <TextBlock Text="{Binding SuperChatAmount, StringFormat=${0:F2}}"
+                                                   Foreground="#eab308" FontWeight="Bold" FontSize="12"
+                                                   Margin="8,0,0,0" VerticalAlignment="Center"
+                                                   Visibility="{Binding IsSuperChat, Converter={StaticResource BoolToVis}}"/>
+                                        <TextBlock Text="{Binding SuperChatCurrency}" Foreground="#eab308"
+                                                   FontSize="11" Margin="2,0,0,0" VerticalAlignment="Center"
+                                                   Visibility="{Binding IsSuperChat, Converter={StaticResource BoolToVis}}"/>
+                                    </StackPanel>
+                                    <TextBlock Text="{Binding Message}" Foreground="#e0e0e0"
+                                               TextWrapping="Wrap" Margin="0,2,0,0"/>
+                                </StackPanel>
+                            </Border>
+                        </DataTemplate></ListBox.ItemTemplate>
+                    </ListBox>
+                </Grid>
+            </Grid>
+    </Border>
+</UserControl>

Controls/LeftPanel.xaml.cs

@@ -0,0 +1,289 @@
+using System.Collections;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+using ytLive.Models;
+using ytLive.ViewModels;
+
+namespace ytLive.Controls;
+
+public partial class LeftPanel : UserControl
+{
+    private Models.SceneElement? _snapshotElement;
+    private string _snapshotBorderColor = string.Empty;
+    private int _snapshotBorderWidth;
+    private int _snapshotTimerMinutes = 15;
+    private string? _snapshotWebUri;
+
+    private Point _dragStartPoint;
+    private int _dragIndex = -1;
+    private bool _isDragging;
+    private object? _lastHoveredItem;
+    private bool _dragReordered;
+
+    public LeftPanel()
+    {
+        InitializeComponent();
+        Loaded += (_, _) =>
+        {
+            if (DataContext is MainViewModel vm)
+                vm.ChatMessages.CollectionChanged += OnChatMessagesChanged;
+        };
+        Unloaded += (_, _) =>
+        {
+            if (DataContext is MainViewModel vm)
+                vm.ChatMessages.CollectionChanged -= OnChatMessagesChanged;
+        };
+    }
+
+    // Called by the window's UpdateSelectionOverlay (edit mode only).
+    public void OnSelectionChanged(MainViewModel vm)
+    {
+        if (vm.SelectedElement is { } s && PreviewPane.IsDraggableElement(s))
+            OpacityValueText.Text = $"{Math.Round(s.Opacity * 100)}%";
+        TakeSnapshot(vm);
+    }
+
+    // Deselection guard: true when the click is inside the source list or the
+    // element property scroller (window's Window_PreviewMouseLeftButtonDown).
+    public bool IsClickInside(DependencyObject original)
+        => IsDescendantOf(original, SourceList) || IsDescendantOf(original, ElementsScrollViewer);
+
+    private static bool IsDescendantOf(DependencyObject? child, DependencyObject ancestor)
+    {
+        while (child != null && !ReferenceEquals(child, ancestor))
+        {
+            var next = child is Visual or System.Windows.Media.Media3D.Visual3D
+                ? VisualTreeHelper.GetParent(child)
+                : null;
+            child = next
+                ?? LogicalTreeHelper.GetParent(child)
+                ?? (child as FrameworkElement)?.TemplatedParent;
+        }
+        return child != null;
+    }
+
+    private void SourceNameBox_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
+    {
+        if (sender is TextBox { IsVisible: true } box)
+        {
+            box.Focus();
+            box.SelectAll();
+        }
+    }
+
+    private void AddSourceButton_Click(object sender, RoutedEventArgs e)
+    {
+        if (sender is Button { ContextMenu: { } menu } button)
+        {
+            menu.PlacementTarget = button;
+            menu.Placement = System.Windows.Controls.Primitives.PlacementMode.Bottom;
+            menu.IsOpen = true;
+        }
+    }
+
+    private void OnChatMessagesChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+    {
+        if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
+        {
+            ChatListBox.ScrollIntoView(ChatListBox.Items[^1]);
+        }
+    }
+
+    private void MirrorButton_Click(object sender, RoutedEventArgs e)
+    {
+        if ((DataContext as MainViewModel)?.SelectedElement is WebcamSceneConfig webcam)
+            webcam.IsMirrored = !webcam.IsMirrored;
+    }
+
+    private void SourceMenu_Remove(object sender, RoutedEventArgs e)
+    {
+        if (sender is MenuItem { DataContext: SceneElement element } && DataContext is MainViewModel vm)
+            vm.RemoveSourceCommand.Execute(element);
+    }
+
+    private void BackgroundMenu_ChangeCapture(object sender, RoutedEventArgs e)
+    {
+        _ = (DataContext as MainViewModel)?.ChangeBackgroundCaptureAsync();
+    }
+
+    private void BackgroundMenu_RefreshCapture(object sender, RoutedEventArgs e)
+    {
+        (DataContext as MainViewModel)?.RefreshBackgroundAutoCapture();
+    }
+
+    private void BackgroundMenu_RefreshWindowList(object sender, RoutedEventArgs e)
+    {
+        (DataContext as MainViewModel)?.RefreshWindowsCommand.Execute(null);
+    }
+
+    private void OpacitySlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
+        => OpacityValueText.Text = $"{Math.Round(e.NewValue * 100)}%";
+
+    private void SourceNameBox_KeyDown(object sender, KeyEventArgs e)
+    {
+        if (e.Key is Key.Enter or Key.Escape)
+        {
+            CommitSourceEdit(sender);
+            e.Handled = true;
+        }
+    }
+
+    private void SourceNameBox_LostFocus(object sender, RoutedEventArgs e)
+    {
+        CommitSourceEdit(sender);
+    }
+
+    private static void CommitSourceEdit(object sender)
+    {
+        if (sender is FrameworkElement { DataContext: SceneElement element })
+            element.IsEditing = false;
+    }
+
+    // ─── List drag-to-reorder (scenes list + sources list) ───
+    private void List_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        var listBox = (ListBox)sender;
+        var item = FindItemContainerAt(listBox, e.GetPosition(listBox));
+        if (item == null)
+        {
+            if (ReferenceEquals(listBox, SourceList))
+                (DataContext as MainViewModel)!.SelectedElement = null;
+            _dragIndex = -1;
+            return;
+        }
+        if (listBox.ItemsSource is not IList items || items.Count == 0)
+        {
+            _dragIndex = -1;
+            return;
+        }
+        _dragIndex = listBox.Items.IndexOf(item.DataContext);
+        _dragStartPoint = e.GetPosition(listBox);
+        _isDragging = false;
+        _lastHoveredItem = null;
+        _dragReordered = false;
+    }
+
+    private void List_PreviewMouseMove(object sender, MouseEventArgs e)
+    {
+        if (_dragIndex < 0) return;
+        var listBox = (ListBox)sender;
+        if (e.LeftButton != MouseButtonState.Pressed || listBox.ItemsSource is not IList items)
+        {
+            EndListDrag(listBox);
+            return;
+        }
+
+        var position = e.GetPosition(listBox);
+        if (!_isDragging)
+        {
+            if (Math.Abs(position.X - _dragStartPoint.X) < SystemParameters.MinimumHorizontalDragDistance &&
+                Math.Abs(position.Y - _dragStartPoint.Y) < SystemParameters.MinimumVerticalDragDistance)
+                return;
+            _isDragging = true;
+            listBox.CaptureMouse();
+        }
+
+        var item = FindItemContainerAt(listBox, position);
+        if (item == null) return;
+
+        var targetItem = item.DataContext;
+        if (ReferenceEquals(targetItem, items[_dragIndex]) || ReferenceEquals(targetItem, _lastHoveredItem))
+            return;
+
+        var targetIndex = listBox.Items.IndexOf(targetItem);
+        if (targetIndex < 0) return;
+
+        var dragged = items[_dragIndex];
+        items.RemoveAt(_dragIndex);
+        items.Insert(targetIndex, dragged);
+        _dragIndex = targetIndex;
+        _lastHoveredItem = targetItem;
+        _dragReordered = true;
+    }
+
+    private void List_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        EndListDrag((ListBox)sender);
+    }
+
+    private void EndListDrag(ListBox listBox)
+    {
+        if (_isDragging)
+            listBox.ReleaseMouseCapture();
+        var reordered = _dragReordered;
+        _dragIndex = -1;
+        _isDragging = false;
+        _lastHoveredItem = null;
+        _dragReordered = false;
+        if (reordered && DataContext is MainViewModel vm)
+            vm.OnSceneElementsReordered();
+    }
+
+    private static ListBoxItem? FindItemContainerAt(ListBox listBox, Point position)
+    {
+        var hit = listBox.InputHitTest(position) as DependencyObject;
+        while (hit != null && hit != listBox)
+        {
+            if (hit is ListBoxItem item) return item;
+            hit = VisualTreeHelper.GetParent(hit);
+        }
+        return null;
+    }
+
+    private void TakeSnapshot(MainViewModel vm)
+    {
+        if (vm.SelectedElement is Models.Source src)
+        {
+            _snapshotElement = src;
+            _snapshotBorderColor = src.BorderColor;
+            _snapshotBorderWidth = src.BorderWidth;
+            _snapshotTimerMinutes = src.TimerMinutes;
+            _snapshotWebUri = src.WebUri;
+        }
+    }
+
+    private void WebcamBorderRevert_Click(object sender, RoutedEventArgs e)
+    {
+        if (_snapshotElement is Models.Source src)
+        {
+            src.BorderColor = _snapshotBorderColor;
+            src.BorderWidth = _snapshotBorderWidth;
+        }
+    }
+
+    private void WebcamBorderAccept_Click(object sender, RoutedEventArgs e)
+    {
+        if (_snapshotElement is Models.Source src)
+        {
+            _snapshotBorderColor = src.BorderColor;
+            _snapshotBorderWidth = src.BorderWidth;
+        }
+    }
+
+    private void CountdownRevert_Click(object sender, RoutedEventArgs e)
+    {
+        if (_snapshotElement is Models.Source src)
+            src.TimerMinutes = _snapshotTimerMinutes;
+    }
+
+    private void CountdownAccept_Click(object sender, RoutedEventArgs e)
+    {
+        if (_snapshotElement is Models.Source src)
+            _snapshotTimerMinutes = src.TimerMinutes;
+    }
+
+    private void WebRevert_Click(object sender, RoutedEventArgs e)
+    {
+        if (_snapshotElement is Models.Source src)
+            src.WebUri = string.Empty;
+        _snapshotWebUri = string.Empty;
+    }
+
+    private void WebAccept_Click(object sender, RoutedEventArgs e)
+    {
+        if (_snapshotElement is Models.Source src)
+            _snapshotWebUri = src.WebUri;
+    }
+}

Controls/OverlayHost.xaml

@@ -0,0 +1,179 @@
+<UserControl x:Class="ytLive.Controls.OverlayHost"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:Helpers="clr-namespace:ytLive.Helpers"
+             xmlns:Models="clr-namespace:ytLive.Models">
+        <Grid Grid.RowSpan="3"
+              Visibility="{Binding IsAnyOverlayOpen, Converter={StaticResource BoolToVis}}">
+            <Button Background="#99000000" BorderThickness="0" Cursor="Hand"
+                    Command="{Binding CloseOverlayCommand}">
+                <Button.Template>
+                    <ControlTemplate TargetType="Button">
+                        <Border Background="{TemplateBinding Background}"/>
+                    </ControlTemplate>
+                </Button.Template>
+            </Button>
+
+            <Border Background="#0A0C1A" CornerRadius="8" Width="650" MaxHeight="700"
+                    VerticalAlignment="Center" HorizontalAlignment="Center"
+                    Padding="28" BorderBrush="#333" BorderThickness="1">
+                <Grid>
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto"/>
+                        <RowDefinition Height="Auto"/>
+                    </Grid.RowDefinitions>
+
+                    <!-- Header -->
+                    <Grid Grid.Row="0">
+                        <TextBlock Text="{Binding OverlayTitle}" FontSize="18" FontWeight="Bold"
+                                   Foreground="#e0e0e0" VerticalAlignment="Center"/>
+                        <Button HorizontalAlignment="Right" ToolTip="Close" Style="{StaticResource IconButton}"
+                                Command="{Binding CloseOverlayCommand}">
+                            <Path Data="M19,6.41L17.59,5 12,10.59 6.41,5 5,6.41 10.59,12 5,17.59 6.41,19 12,13.41 17.59,19 19,17.59 13.41,12z"
+                                  Fill="#d0d0d0" Width="14" Height="14" Stretch="Uniform"/>
+                        </Button>
+                    </Grid>
+
+                    <!-- App Settings: broadcast fields live in the preview's
+                         Text pull-out now — this panel keeps app-level prefs only.
+                         (Currently empty; the overlay shell stays for future use.) -->
+                    <StackPanel Grid.Row="1" Margin="0,16,0,0"
+                                Visibility="{Binding IsSettingsOpen, Converter={StaticResource BoolToVis}}">
+                        <TextBlock Text="Default Location for Recordings" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <TextBox Style="{StaticResource YtTextBox}" 
+                                 Text="{Binding RecordFolderDisplay, Mode=OneWay}"
+                                 IsReadOnly="True" Margin="0,0,0,12" Foreground="#a0a0b0"/>
+                        <StackPanel Orientation="Horizontal" Margin="0,0,0,16">
+                            <Button Content="Browse…" Command="{Binding ChooseRecordFolderCommand}"
+                                    Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
+                            <Button Content="Use Downloads" Command="{Binding ResetRecordFolderCommand}"
+                                    Style="{StaticResource YtButtonSecondary}"/>
+                        </StackPanel>
+                        <TextBlock Text="Zoom View Shape" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <ComboBox Style="{StaticResource YtComboBox}" SelectedValue="{Binding ZoomShape}" SelectedValuePath="Tag">
+                            <ComboBoxItem Content="Circle" Tag="{x:Static Models:ZoomShape.Circle}"/>
+                            <ComboBoxItem Content="Phone (Vertical Rectangle)" Tag="{x:Static Models:ZoomShape.VerticalRectangle}"/>
+                            <ComboBoxItem Content="Tablet (Horizontal Rectangle)" Tag="{x:Static Models:ZoomShape.HorizontalRectangle}"/>
+                        </ComboBox>
+                    </StackPanel>
+
+                    <!-- Report Bug -->
+                    <StackPanel Grid.Row="1" Margin="0,16,0,0"
+                                Visibility="{Binding IsBugOpen, Converter={StaticResource BoolToVis}}">
+                        <TextBlock Text="What went wrong?" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <TextBox Style="{StaticResource YtTextBox}" Height="110" AcceptsReturn="True" TextWrapping="Wrap"
+                                 Margin="0,0,0,12"
+                                 Text="{Binding BugReportText, UpdateSourceTrigger=PropertyChanged}"
+                                 VerticalScrollBarVisibility="Auto"/>
+
+                        <TextBlock Text="Email (optional)" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <TextBox Style="{StaticResource YtTextBox}" Margin="0,0,0,12"
+                                 Text="{Binding BugReportEmail, UpdateSourceTrigger=PropertyChanged}"/>
+
+                        <TextBlock Text="Opens a pre-filled email to the LlamaCasty team." Style="{StaticResource YtLabel}"/>
+                        <Button Content="Send Report" Command="{Binding SubmitBugCommand}"
+                                Style="{StaticResource YtButton}" HorizontalAlignment="Right" Margin="0,16,0,0"/>
+                    </StackPanel>
+
+                    <!-- Feature Request -->
+                    <StackPanel Grid.Row="1" Margin="0,16,0,0"
+                                Visibility="{Binding IsFeatureOpen, Converter={StaticResource BoolToVis}}">
+                        <TextBlock Text="What would you like to see?" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <TextBox Style="{StaticResource YtTextBox}" Height="110" AcceptsReturn="True" TextWrapping="Wrap"
+                                 Margin="0,0,0,12"
+                                 Text="{Binding FeatureRequestText, UpdateSourceTrigger=PropertyChanged}"
+                                 VerticalScrollBarVisibility="Auto"/>
+
+                        <TextBlock Text="Email (optional)" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                        <TextBox Style="{StaticResource YtTextBox}" Margin="0,0,0,12"
+                                 Text="{Binding FeatureRequestEmail, UpdateSourceTrigger=PropertyChanged}"/>
+
+                        <TextBlock Text="Opens a pre-filled email to the LlamaCasty team." Style="{StaticResource YtLabel}"/>
+                        <Button Content="Send Request" Command="{Binding SubmitFeatureCommand}"
+                                Style="{StaticResource YtButton}" HorizontalAlignment="Right" Margin="0,16,0,0"/>
+                    </StackPanel>
+
+                    <!-- About -->
+                    <Grid Grid.Row="1" Margin="0,16,0,0"
+                          Background="#171928"
+                          Visibility="{Binding IsAboutOpen, Converter={StaticResource BoolToVis}}">
+
+                        <!-- Hub view -->
+                        <StackPanel Visibility="{Binding IsHubVisible, Converter={StaticResource BoolToVis}}">
+                            <Image Source="/ytLive;component/Assets/llamacasty-logo.jpg" Height="125" Stretch="Uniform"
+                                   HorizontalAlignment="Center" Margin="0,0,0,12"/>
+                            <TextBlock Text="{Binding AppVersionLabel}" Foreground="#a0a0b0" FontSize="12"
+                                       HorizontalAlignment="Center" Margin="0,4,0,0"/>
+                            <TextBlock Text="Live streaming for YouTube — simple enough that even the most right-brained person can intuit it."
+                                       Foreground="#a0a0b0" FontSize="13" TextWrapping="Wrap" MaxWidth="380"
+                                       TextAlignment="Center" Margin="0,16,0,0"/>
+                            <TextBlock Text="Free forever — live streams carry a brief &quot;made with LlamaCasty!&quot; flash. A subscription removes it and adds alerts."
+                                       Foreground="#888" FontSize="12" TextWrapping="Wrap" MaxWidth="380"
+                                       TextAlignment="Center" Margin="0,12,0,0"/>
+                            <TextBlock Text="Made by gramps · llama chile shop" Foreground="#a0a0b0" FontSize="12"
+                                       HorizontalAlignment="Center" Margin="0,16,0,8"/>
+
+                            <!-- Creator hub links -->
+                            <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,0,0,8">
+                                <Button Content="llama chile shop on YouTube" Command="{Binding OpenChannelCommand}"
+                                        Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
+                                <Button Content="Mastodon" Command="{Binding OpenMastodonCommand}"
+                                        Style="{StaticResource YtButtonSecondary}"/>
+                            </StackPanel>
+                            <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
+                                <Button Content="Buy me a coffee" Command="{Binding OpenCoffeeCommand}"
+                                        Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
+                                <Button Content="Unlock Premium" Command="{Binding OpenPremiumCommand}"
+                                        Style="{StaticResource YtButtonSecondary}"
+                                        IsEnabled="{Binding IsPremiumAvailable}"
+                                        ToolTip="Open the LlamaCasty subscription page"/>
+                                <Button Content="Enter License Key" Command="{Binding OpenLicenseEntryCommand}"
+                                        Style="{StaticResource YtButtonSecondary}"
+                                        ToolTip="Activate a license key to remove the watermark"/>
+                            </StackPanel>
+
+                            <Button Content="Licenses &amp; legal" Command="{Binding OpenLicensesCommand}"
+                                    Style="{StaticResource YtButtonSecondary}" HorizontalAlignment="Center"
+                                    Margin="0,16,0,0"/>
+                        </StackPanel>
+
+                        <!-- Licensing/legal panel -->
+                        <StackPanel Visibility="{Binding IsLicensesOpen, Converter={StaticResource BoolToVis}}">
+                            <TextBlock Text="Third-party notices &amp; license texts" FontSize="15" FontWeight="Bold"
+                                       Foreground="#e0e0e0" Margin="0,0,0,8"/>
+                            <Border Background="#10101e" CornerRadius="4" Padding="10" MaxHeight="360"
+                                    BorderBrush="#333" BorderThickness="1">
+                                <ScrollViewer VerticalScrollBarVisibility="Auto">
+                                    <TextBlock Text="{Binding LicensesText}" Foreground="#b8b8c8" FontSize="11"
+                                               FontFamily="Consolas" TextWrapping="Wrap"/>
+                                </ScrollViewer>
+                            </Border>
+                            <Button Content="← Back to About" Style="{StaticResource YtButtonSecondary}"
+                                    HorizontalAlignment="Left" Margin="0,12,0,0"
+                                    Click="BackToAbout_Click"/>
+                        </StackPanel>
+
+                        <!-- License key entry panel -->
+                        <StackPanel Visibility="{Binding IsLicenseEntryOpen, Converter={StaticResource BoolToVis}}">
+                            <TextBlock Text="Activate LlamaCasty Premium" FontSize="15" FontWeight="Bold"
+                                       Foreground="#e0e0e0" Margin="0,0,0,8"/>
+                            <TextBlock Text="Enter your license key to remove the branding watermark."
+                                       Foreground="#a0a0b0" FontSize="12" TextWrapping="Wrap" Margin="0,0,0,12"/>
+                            <TextBlock Text="License Key" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                            <TextBox Style="{StaticResource YtTextBox}" Margin="0,0,0,12"
+                                     Text="{Binding LicenseKey, UpdateSourceTrigger=PropertyChanged}"
+                                     MaxLength="100"/>
+                            <Button Content="Activate" Command="{Binding ActivateLicenseCommand}"
+                                    Style="{StaticResource YtButton}" HorizontalAlignment="Right"
+                                    Margin="0,0,0,8"/>
+                            <TextBlock Text="{Binding LicenseMessage}" Foreground="#a0a0b0" FontSize="12"
+                                       TextWrapping="Wrap" Margin="0,0,0,8"/>
+                            <Button Content="← Back to About" Style="{StaticResource YtButtonSecondary}"
+                                    HorizontalAlignment="Left" Margin="0,8,0,0"
+                                    Click="BackToAbout_Click"/>
+                        </StackPanel>
+                    </Grid>
+                </Grid>
+            </Border>
+        </Grid>
+</UserControl>

Controls/OverlayHost.xaml.cs

@@ -0,0 +1,22 @@
+using System.Windows;
+using System.Windows.Controls;
+using ytLive.ViewModels;
+
+namespace ytLive.Controls;
+
+public partial class OverlayHost : UserControl
+{
+    public OverlayHost()
+    {
+        InitializeComponent();
+    }
+
+    private void BackToAbout_Click(object sender, RoutedEventArgs e)
+    {
+        if (DataContext is MainViewModel vm)
+        {
+            vm.IsLicensesOpen = false;
+            vm.IsLicenseEntryOpen = false;
+        }
+    }
+}

Controls/PreviewPane.xaml.cs

@@ -0,0 +1,602 @@
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Effects;
+using System.Windows.Media.Animation;
+using System.Windows.Shapes;
+using System.Windows.Threading;
+using ytLive.Helpers;
+using ytLive.Models;
+using ytLive.ViewModels;
+
+namespace ytLive.Controls;
+
+public partial class PreviewPane : UserControl
+{
+    private bool _isDraggingOverlay;
+    private bool _isResizing;
+    private bool _isZoomDragging;
+    private Point _grabOffset;
+    private double _resizeAspect;
+
+    private readonly System.Collections.Generic.Dictionary<string, Storyboard> _activeBorderAnimations =
+        new();
+
+    private DispatcherTimer? _socialGlowTimer;
+    private double _socialGlowAngle;
+
+    public PreviewPane()
+    {
+        InitializeComponent();
+        DataContextChanged += PreviewPane_DataContextChanged;
+    }
+
+    private void PreviewPane_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
+    {
+        if (e.OldValue is MainViewModel oldVm)
+            oldVm.PropertyChanged -= ViewModel_PropertyChanged;
+        if (e.NewValue is MainViewModel newVm)
+        {
+            newVm.PropertyChanged += ViewModel_PropertyChanged;
+            UpdateZoomBox();
+        }
+    }
+
+    private void ViewModel_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
+    {
+        if (e.PropertyName == nameof(MainViewModel.IsZoomActive) || e.PropertyName == nameof(MainViewModel.ZoomState) || e.PropertyName == nameof(MainViewModel.ZoomShape))
+        {
+            UpdateZoomBox();
+        }
+    }
+
+
+
+    // Static images and the webcam share the move/resize/selection behavior.
+    public static bool IsDraggableElement(SceneElement element)
+        => element.IsDraggable;
+
+    public void UpdateSelectionOverlay(bool selected)
+    {
+        SelectionOverlay.Visibility = selected ? Visibility.Visible : Visibility.Collapsed;
+    }
+
+    // ─── Clicking inside the preview / pull-out drawer (used by the window's
+    //     Window_PreviewMouseLeftButtonDown deselection logic) ───
+    public bool IsClickInsidePreview(DependencyObject original)
+        => IsDescendantOf(original, PreviewGrid);
+
+    public bool IsClickInsideDrawer(DependencyObject original)
+        => IsDescendantOf(original, TextPullOutHost);
+
+    private static bool IsDescendantOf(DependencyObject? child, DependencyObject ancestor)
+    {
+        while (child != null && !ReferenceEquals(child, ancestor))
+        {
+            child = child is Visual or System.Windows.Media.Media3D.Visual3D
+                ? VisualTreeHelper.GetParent(child)
+                : LogicalTreeHelper.GetParent(child);
+        }
+        return child != null;
+    }
+
+    // ─── Audio meters + TRAX + socials (ROW 2 of the preview pane) ───
+    private void VolumeSlider_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is Slider slider)
+            SetSliderValueFromClick(slider, e);
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+            vm.SetVolumeAdjusting(true);
+    }
+
+    private void VolumeSlider_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+            vm.SetVolumeAdjusting(false);
+    }
+
+    private void VolumeSlider_LostMouseCapture(object sender, MouseEventArgs e)
+    {
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+            vm.SetVolumeAdjusting(false);
+    }
+
+    private void GameVolumeSlider_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is Slider slider)
+            SetSliderValueFromClick(slider, e);
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+            vm.SetGameVolumeAdjusting(true);
+    }
+
+    private void GameVolumeSlider_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+            vm.SetGameVolumeAdjusting(false);
+    }
+
+    private void GameVolumeSlider_LostMouseCapture(object sender, MouseEventArgs e)
+    {
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+            vm.SetGameVolumeAdjusting(false);
+    }
+
+    private static void SetSliderValueFromClick(Slider slider, MouseButtonEventArgs e)
+    {
+        if (FindParent<System.Windows.Controls.Primitives.Thumb>(e.OriginalSource as Visual) != null)
+            return;
+        var track = slider.Template.FindName("PART_Track", slider) as System.Windows.Controls.Primitives.Track;
+        if (track == null) return;
+        var pos = e.GetPosition(track);
+        var fraction = Math.Clamp(pos.X / track.RenderSize.Width, 0, 1);
+        slider.Value = slider.Minimum + fraction * (slider.Maximum - slider.Minimum);
+        e.Handled = true;
+    }
+
+    private static T? FindParent<T>(Visual? visual) where T : Visual
+    {
+        while (visual != null)
+        {
+            if (visual is T match) return match;
+            visual = VisualTreeHelper.GetParent(visual) as Visual;
+        }
+        return null;
+    }
+
+    private void MicSpeaker_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+        {
+            vm.ToggleMicMuteCommand.Execute(null);
+        }
+    }
+
+    private void GameSpeaker_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is FrameworkElement { DataContext: MainViewModel vm })
+        {
+            vm.ToggleGameMuteCommand.Execute(null);
+        }
+    }
+
+    // TRAX (TASK 9): left-click toggles play/pause (picks a track when none is
+    // loaded); right-click always opens the picker. The picker is the OS file
+    // dialog — the "never the OS viewer" rule covers the preview, not pickers.
+    private void TraxButton_Click(object sender, RoutedEventArgs e)
+    {
+        if (DataContext is ViewModels.MainViewModel vm)
+            vm.TraxLeftClick();
+    }
+
+    private void TraxButton_PreviewMouseRightButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (DataContext is ViewModels.MainViewModel vm)
+            vm.TraxRightClick();
+        e.Handled = true; // the button's right-click context menu must not fire
+    }
+
+    // ─── Webcam / background context menus (right-click on overlay elements) ───
+    private void WebcamMenu_ChangeWebcam(object sender, RoutedEventArgs e)
+        => (DataContext as MainViewModel)?.ChangeWebcamCommand.Execute(null);
+
+    private void WebcamMenu_SetBorderAnimation(object sender, RoutedEventArgs e)
+    {
+        if (sender is not MenuItem { DataContext: SceneElement element, Tag: string tag }
+            || !Enum.TryParse<BorderAnimation>(tag, out var animation))
+            return;
+
+        element.BorderAnimation = animation;
+
+        StopBorderAnimation(element.Id);
+
+        if (animation == BorderAnimation.None) return;
+
+        var shape = FindBorderShape(sender as DependencyObject);
+        if (shape == null) return;
+
+        var sb = CreateBorderAnimation(animation, shape);
+        if (sb == null) return;
+
+        sb.Freeze();
+        _activeBorderAnimations[element.Id] = sb;
+        shape.BeginAnimation(Shape.OpacityProperty, null);
+        Storyboard.SetTarget(sb, shape);
+        sb.Begin();
+    }
+
+    private void StopBorderAnimation(string elementId)
+    {
+        if (_activeBorderAnimations.TryGetValue(elementId, out var old))
+        {
+            old.Stop();
+            _activeBorderAnimations.Remove(elementId);
+        }
+    }
+
+    private static Shape? FindBorderShape(DependencyObject? start)
+    {
+        var current = start;
+        while (current != null)
+        {
+            if (current is ContextMenu cm && cm.PlacementTarget is FrameworkElement target)
+            {
+                for (var i = 0; i < VisualTreeHelper.GetChildrenCount(target); i++)
+                {
+                    var child = VisualTreeHelper.GetChild(target, i);
+                    if (child is Shape s && (s is Rectangle or Ellipse) && !s.IsHitTestVisible)
+                        return s;
+                }
+                return null;
+            }
+            current = VisualTreeHelper.GetParent(current);
+        }
+        return null;
+    }
+
+    private static Storyboard? CreateBorderAnimation(BorderAnimation animation, Shape shape)
+    {
+        var sb = new Storyboard();
+        switch (animation)
+        {
+            case BorderAnimation.Pulse:
+                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.3, TimeSpan.FromSeconds(0.8), true);
+                break;
+            case BorderAnimation.Glow:
+                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.5, TimeSpan.FromSeconds(1.2), true);
+                break;
+            case BorderAnimation.Shimmer:
+                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.15, TimeSpan.FromSeconds(0.5), true);
+                break;
+            case BorderAnimation.Electricity:
+                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.2, TimeSpan.FromSeconds(0.1), true);
+                break;
+            case BorderAnimation.Sparkles:
+                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.4, TimeSpan.FromSeconds(0.3), true);
+                break;
+            case BorderAnimation.MarchingAnts:
+                shape.StrokeDashArray = new DoubleCollection { 4, 2 };
+                AddDoubleAnimation(sb, Shape.StrokeDashOffsetProperty, 0, -20, TimeSpan.FromSeconds(0.8), false);
+                break;
+            case BorderAnimation.Chase:
+                shape.StrokeDashArray = new DoubleCollection { 8, 4 };
+                AddDoubleAnimation(sb, Shape.StrokeDashOffsetProperty, 0, -30, TimeSpan.FromSeconds(1.5), false);
+                break;
+            case BorderAnimation.Rainbow:
+                if (shape.Stroke is SolidColorBrush brush)
+                {
+                    var frozen = brush.IsFrozen;
+                    if (frozen) brush = brush.Clone();
+                    shape.Stroke = brush;
+                    var colorAnim = new ColorAnimationUsingKeyFrames
+                    {
+                        Duration = new Duration(TimeSpan.FromSeconds(3)),
+                        RepeatBehavior = RepeatBehavior.Forever
+                    };
+                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Red, KeyTime.FromTimeSpan(TimeSpan.Zero)));
+                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Yellow, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(0.5))));
+                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Green, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1))));
+                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.DodgerBlue, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.5))));
+                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.MediumPurple, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2))));
+                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Red, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.5))));
+                    Storyboard.SetTargetProperty(colorAnim, new PropertyPath("(Shape.Stroke).(SolidColorBrush.Color)"));
+                    sb.Children.Add(colorAnim);
+                }
+                break;
+            default:
+                return null;
+        }
+        return sb.Children.Count > 0 ? sb : null;
+    }
+
+    private static void AddDoubleAnimation(Storyboard sb, DependencyProperty prop,
+        double from, double to, Duration duration, bool autoReverse)
+    {
+        var anim = new DoubleAnimation(from, to, duration)
+        {
+            AutoReverse = autoReverse,
+            RepeatBehavior = RepeatBehavior.Forever
+        };
+        Storyboard.SetTargetProperty(anim, new PropertyPath(prop));
+        sb.Children.Add(anim);
+    }
+
+    private void WebcamMenu_SetBorderColor(object sender, RoutedEventArgs e)
+    {
+        if (sender is MenuItem { DataContext: SceneElement element, Tag: string color })
+            element.BorderColor = color;
+    }
+
+    private void WebcamMenu_HideInScene(object sender, RoutedEventArgs e)
+    {
+        if (sender is MenuItem { DataContext: SceneElement element })
+            element.IsVisible = false;
+    }
+
+    private void WebcamMenu_Remove(object sender, RoutedEventArgs e)
+    {
+        if (sender is MenuItem { DataContext: SceneElement element })
+            (DataContext as MainViewModel)?.RemoveSourceCommand.Execute(element);
+    }
+
+    // ─── Social bar: click toggles top ⇄ bottom. KISS — the drag variant was
+    // unusable for shaky hands (jitter around the direction deadzone), so the bar
+    // rides on {Binding SocialBarTop} alone and a click flips it. ───
+    private void SocialBar_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        (DataContext as MainViewModel)?.ToggleSocialBarPosition();
+        e.Handled = true;
+    }
+
+    private void SocialsButton_MouseEnter(object sender, MouseEventArgs e)
+    {
+        if (SocialBarElement == null) return;
+
+        // Kick the social bar to full brightness so it's immediately visible
+        var effect = SocialBarElement.Effect as DropShadowEffect;
+        if (effect != null)
+        {
+            effect.BlurRadius = 40;
+            effect.Opacity = 1.0;
+        }
+
+        // Pulse the glow so it catches the eye
+        _socialGlowAngle = 0;
+        _socialGlowTimer?.Stop();
+        _socialGlowTimer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(30) };
+        _socialGlowTimer.Tick += SocialGlowTick;
+        _socialGlowTimer.Start();
+    }
+
+    private void SocialsButton_MouseLeave(object sender, MouseEventArgs e)
+    {
+        _socialGlowTimer?.Stop();
+        _socialGlowTimer = null;
+
+        if (SocialBarElement?.Effect is DropShadowEffect effect)
+        {
+            effect.BlurRadius = 18;
+            effect.Opacity = 0.9;
+        }
+    }
+
+    private void SocialGlowTick(object? sender, EventArgs e)
+    {
+        if (SocialBarElement?.Effect is not DropShadowEffect effect) return;
+
+        _socialGlowAngle += 0.18;
+        if (_socialGlowAngle > Math.PI * 2) _socialGlowAngle -= Math.PI * 2;
+
+        // Smooth sine pulse: BlurRadius 24→48, Opacity 0.7→1.0
+        double t = (Math.Sin(_socialGlowAngle) + 1.0) / 2.0; // 0..1
+        effect.BlurRadius = 24 + t * 24;
+        effect.Opacity = 0.7 + t * 0.3;
+    }
+
+    // ─── Preview: element selection / move / resize / hit-testing ───
+    private void Preview_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        var vm = DataContext as MainViewModel;
+        if (vm is null || !vm.IsEditMode) return;
+        var grid = (Grid)sender;
+        var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
+        var p = toCanvas.Transform(e.GetPosition(grid));
+        var selected = vm.SelectedElement;
+
+        if (selected is { } sel && IsDraggableElement(sel) && HitHandle(e.GetPosition(grid), sel))
+        {
+            _isResizing = true;
+            _resizeAspect = sel.ClipShape == ClipShape.Round ? 1 : sel.Width / Math.Max(1, sel.Height);
+            grid.CaptureMouse();
+            e.Handled = true;
+            return;
+        }
+
+        var hit = HitElement(vm, p);
+        if (hit != null)
+        {
+            vm.SelectedElement = hit;
+            _isDraggingOverlay = true;
+            _grabOffset = new Point(p.X - hit.X, p.Y - hit.Y);
+            grid.CaptureMouse();
+            e.Handled = true;
+            return;
+        }
+
+        vm.SelectedElement = null;
+    }
+
+    private void Preview_MouseMove(object sender, MouseEventArgs e)
+    {
+        var vm = DataContext as MainViewModel;
+        if (vm is null) return;
+        var grid = (Grid)sender;
+        var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
+        var p = toCanvas.Transform(e.GetPosition(grid));
+
+        if (e.LeftButton == MouseButtonState.Pressed && vm.IsZoomActive)
+        {
+            if (!_isZoomDragging)
+            {
+                vm.StartZoomMove(p.X, p.Y);
+                _isZoomDragging = true;
+                grid.CaptureMouse();
+            }
+            else
+            {
+                vm.UpdateZoomMove(p.X, p.Y);
+            }
+            return;
+        }
+
+        if (!vm.IsEditMode) return;
+        if (!_isDraggingOverlay && !_isResizing) return;
+
+        var selected = vm.SelectedElement;
+        if (selected == null)
+        {
+            EndPreviewDrag(grid);
+            return;
+        }
+
+        if (_isDraggingOverlay)
+        {
+            // TASK 57: under the vertical tier the camera snaps into the
+            // cropped band (one of six spots) instead of free-floating over
+            // the master — outside the band it is not in the stream at all.
+            if (vm.IsVerticalTier && selected is WebcamSceneConfig verticalCam)
+            {
+                vm.MoveWebcamInVerticalTier(verticalCam, p.X - _grabOffset.X, p.Y - _grabOffset.Y);
+            }
+            else
+            {
+                var minX = -(selected.Width - 20);
+                var maxX = 1920 - 20;
+                var minY = -(selected.Height - 20);
+                var maxY = 1080 - 20;
+                selected.X = Math.Clamp(p.X - _grabOffset.X, Math.Min(minX, maxX), Math.Max(minX, maxX));
+                selected.Y = Math.Clamp(p.Y - _grabOffset.Y, Math.Min(minY, maxY), Math.Max(minY, maxY));
+            }
+        }
+        else if (_isResizing)
+        {
+            var isWebcam = selected is WebcamSceneConfig;
+            var isRound = selected.ClipShape == ClipShape.Round;
+            var proportional = isRound || Keyboard.Modifiers.HasFlag(ModifierKeys.Shift);
+            var maxW = isWebcam ? MainViewModel.MaxWebcamWidthFor(vm.StagedScene?.Name) : 1920;
+            var maxH = isWebcam ? MainViewModel.MaxWebcamHeightFor(vm.StagedScene?.Name) : 1080;
+            var newW = Math.Clamp(p.X - selected.X, 32, maxW);
+            var newH = proportional ? newW / _resizeAspect : Math.Clamp(p.Y - selected.Y, 32, maxH);
+            if (proportional && newH > maxH)
+            {
+                newH = maxH;
+                newW = newH * _resizeAspect;
+            }
+            selected.Width = newW;
+            selected.Height = newH;
+
+            // TASK 57: inside the vertical band the size snaps (the Chat
+            // camera has two sizes: the small tile or one whole area) and the
+            // camera ends up on its spot.
+            if (vm.IsVerticalTier && selected is WebcamSceneConfig verticalCam)
+                vm.ResizeWebcamInVerticalTier(verticalCam, newW, newH);
+        }
+    }
+
+    private void Preview_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (_isZoomDragging && DataContext is MainViewModel vm)
+        {
+            vm.EndZoomMove();
+            _isZoomDragging = false;
+            ((Grid)sender).ReleaseMouseCapture();
+            e.Handled = true;
+            return;
+        }
+        EndPreviewDrag((Grid)sender);
+    }
+
+    private void Preview_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        var vm = DataContext as MainViewModel;
+        if (vm == null) return;
+        var grid = (Grid)sender;
+        var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
+        var p = toCanvas.Transform(e.GetPosition(grid));
+        if ((vm.IsLive || vm.IsRecording) && !vm.IsEditMode)
+        {
+            if (vm.IsZoomActive)
+            {
+                vm.DismissZoom();
+                e.Handled = true;
+                return;
+            }
+            vm.ActivateZoom(p.X, p.Y);
+            e.Handled = true;
+            return;
+        }
+        vm.ToggleZoom();
+        e.Handled = true;
+    }    private void Preview_MouseRightButtonUp(object sender, MouseButtonEventArgs e)
+    {
+        if (_isZoomDragging)
+        {
+            var grid = (Grid)sender;
+            grid.ReleaseMouseCapture();
+            _isZoomDragging = false;
+            if (DataContext is MainViewModel vm) vm.EndZoomMove();
+            e.Handled = true;
+            return;
+        }
+    }
+
+    private void EndPreviewDrag(Grid grid)
+    {
+        if (_isDraggingOverlay || _isResizing || _isZoomDragging)
+            grid.ReleaseMouseCapture();
+        _isDraggingOverlay = false;
+        _isResizing = false;
+        _isZoomDragging = false;
+        if (DataContext is MainViewModel vm) vm.EndZoomMove();
+    }
+
+    private bool HitHandle(Point mouseScreen, SceneElement element)
+    {
+        var corner = CanvasGrid.TransformToVisual(PreviewGrid).Transform(new Point(element.X + element.Width, element.Y + element.Height));
+        return Math.Abs(mouseScreen.X - corner.X) <= 20 && Math.Abs(mouseScreen.Y - corner.Y) <= 20;
+    }
+
+    private SceneElement? HitElement(MainViewModel vm, Point p)
+    {
+        var scene = vm.StagedScene;
+        if (scene == null) return null;
+        for (var i = scene.Elements.Count - 1; i >= 0; i--)
+        {
+            var element = scene.Elements[i];
+            if (!IsDraggableElement(element)) continue;
+            if (element is Source { IsEnabled: false }) continue;
+            if (element is WebcamSceneConfig { IsVisible: false }) continue;
+            if (p.X >= element.X && p.X <= element.X + element.Width &&
+                p.Y >= element.Y && p.Y <= element.Y + element.Height)
+                return element;
+        }
+        return null;
+    }
+
+    private void UpdateZoomBox()
+    {
+        if (DataContext is not MainViewModel vm) return;
+        if (vm.IsZoomActive && ZoomVisualBrush != null)
+        {
+            // The preview mirrors the output zoom layer: sample the WHOLE composed
+            // preview (CanvasGrid = backdrop + every element layer — the same all-layer
+            // source the output compositor magnifies) at the FIXED capture window (the
+            // box/2 region centred on the click) → 2x via Stretch=Fill. Moving the box
+            // only moves the ZoomBox element; the Viewbox stays glued to the capture.
+            ZoomVisualBrush.Visual = CanvasGrid;
+            ZoomVisualBrush.Viewbox = new Rect(
+                vm.ZoomState.CaptureX,
+                vm.ZoomState.CaptureY,
+                vm.ZoomState.Width / 2,
+                vm.ZoomState.Height / 2);
+            ZoomVisualBrush.ViewboxUnits = BrushMappingMode.Absolute;
+            if (vm.ZoomShape == Models.ZoomShape.Circle)
+            {
+                ZoomCircleOutline.Visibility = Visibility.Visible;
+                ZoomRectOutline.Visibility = Visibility.Collapsed;
+                ZoomBox.Clip = new EllipseGeometry(new Rect(0, 0, vm.ZoomState.Width, vm.ZoomState.Height));
+            }
+            else
+            {
+                ZoomCircleOutline.Visibility = Visibility.Collapsed;
+                ZoomRectOutline.Visibility = Visibility.Visible;
+                ZoomBox.Clip = null;
+            }
+        }
+        else if (!vm.IsZoomActive && ZoomVisualBrush != null && ReferenceEquals(ZoomVisualBrush.Visual, CanvasGrid))
+        {
+            ZoomVisualBrush.Visual = null;
+        }
+    }
+}

Controls/SceneThumbnailStrip.xaml

@@ -0,0 +1,83 @@
+<UserControl x:Class="ytLive.Controls.SceneThumbnailStrip"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    <Border Background="#0d1117" CornerRadius="4" Padding="4">
+        <ItemsControl ItemsSource="{Binding Scenes}" HorizontalAlignment="Center" VerticalAlignment="Center">
+            <ItemsControl.ItemsPanel>
+                <ItemsPanelTemplate>
+                    <StackPanel Orientation="Horizontal"/>
+                </ItemsPanelTemplate>
+            </ItemsControl.ItemsPanel>
+            <ItemsControl.ItemTemplate>
+                <DataTemplate>
+                    <Border Width="196" Height="130" CornerRadius="4" Margin="2" Padding="2"
+                            BorderThickness="2"
+                            Cursor="Hand"
+                            MouseLeftButtonDown="Thumbnail_MouseLeftButtonDown">
+                        <Border.Style>
+                            <Style TargetType="Border">
+                                <Setter Property="BorderBrush" Value="#333344"/>
+                                <Style.Triggers>
+                                    <DataTrigger Binding="{Binding IsStaged}" Value="True">
+                                        <Setter Property="BorderBrush" Value="#ff8c3a"/>
+                                    </DataTrigger>
+                                    <DataTrigger Binding="{Binding IsLive}" Value="True">
+                                        <Setter Property="BorderBrush" Value="#ff8c3a"/>
+                                    </DataTrigger>
+                                </Style.Triggers>
+                            </Style>
+                        </Border.Style>
+                        <Grid>
+                            <Border CornerRadius="3" Background="#0a0a1a" ClipToBounds="True">
+                                <Image Source="{Binding Snapshot}"
+                                       Stretch="UniformToFill"
+                                       RenderOptions.BitmapScalingMode="LowQuality"/>
+                            </Border>
+
+                            <Border HorizontalAlignment="Left" VerticalAlignment="Top" Margin="6" Padding="8,3"
+                                    CornerRadius="3" Background="#ff8c3a">
+                                <Border.Style>
+                                    <Style TargetType="Border">
+                                        <Setter Property="Visibility" Value="Collapsed"/>
+                                        <Style.Triggers>
+                                            <DataTrigger Binding="{Binding IsStaged}" Value="True">
+                                                <Setter Property="Visibility" Value="Visible"/>
+                                            </DataTrigger>
+                                        </Style.Triggers>
+                                    </Style>
+                                </Border.Style>
+                                <StackPanel Orientation="Horizontal">
+                                    <Ellipse Width="8" Height="8" Fill="#ff5451" VerticalAlignment="Center" Margin="0,0,5,0">
+                                        <Ellipse.Triggers>
+                                            <EventTrigger RoutedEvent="FrameworkElement.Loaded">
+                                                <BeginStoryboard>
+                                                    <Storyboard RepeatBehavior="Forever" AutoReverse="True">
+                                                        <DoubleAnimation Storyboard.TargetProperty="Opacity" From="1" To="0.15" Duration="0:0:0.6"/>
+                                                    </Storyboard>
+                                                </BeginStoryboard>
+                                            </EventTrigger>
+                                        </Ellipse.Triggers>
+                                    </Ellipse>
+                                    <TextBlock Text="PROGRAM" Foreground="White" FontSize="11" FontWeight="Bold" VerticalAlignment="Center"/>
+                                </StackPanel>
+                            </Border>
+
+                            <Border HorizontalAlignment="Right" VerticalAlignment="Top" Margin="6" Padding="8,2"
+                                    CornerRadius="10" Background="#000000">
+                                <TextBlock Text="{Binding HotkeyLabel, Mode=OneWay}" Foreground="White" FontSize="16" FontWeight="SemiBold"/>
+                            </Border>
+
+                            <TextBlock Text="{Binding Name, Mode=OneWay}" Foreground="White" FontSize="16" FontWeight="SemiBold"
+                                       HorizontalAlignment="Left" VerticalAlignment="Bottom" Margin="6"
+                                       TextTrimming="CharacterEllipsis">
+                                <TextBlock.Effect>
+                                    <DropShadowEffect BlurRadius="4" ShadowDepth="0" Opacity="0.9"/>
+                                </TextBlock.Effect>
+                            </TextBlock>
+                        </Grid>
+                    </Border>
+                </DataTemplate>
+            </ItemsControl.ItemTemplate>
+        </ItemsControl>
+    </Border>
+</UserControl>

Controls/SceneThumbnailStrip.xaml.cs

@@ -0,0 +1,31 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using ytLive.Models;
+using ytLive.ViewModels;
+
+namespace ytLive.Controls;
+
+public partial class SceneThumbnailStrip : UserControl
+{
+    public SceneThumbnailStrip()
+    {
+        InitializeComponent();
+        Loaded += (_, _) =>
+        {
+            if (DataContext is MainViewModel vm)
+                foreach (var scene in vm.Scenes)
+                {
+                    var staged = scene.IsStaged;
+                    scene.IsStaged = !staged;
+                    scene.IsStaged = staged;
+                }
+        };
+    }
+
+    private void Thumbnail_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
+    {
+        if (sender is Border { DataContext: Scene scene } && DataContext is MainViewModel vm)
+            vm.TransitionToScene(scene);
+    }
+}

Controls/TopBar.xaml

@@ -0,0 +1,150 @@
+<UserControl x:Class="ytLive.Controls.TopBar"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:helpers="clr-namespace:ytLive.Helpers"
+             x:Name="TopBarRoot">
+    <Grid>
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="Auto"/>
+            <ColumnDefinition Width="*"/>
+            <ColumnDefinition Width="Auto"/>
+        </Grid.ColumnDefinitions>
+
+        <!-- LOGO / BRAND — clicking opens the in-app About overlay; the gear sits
+             a couple characters past the build stamp and opens App Settings. -->
+        <StackPanel Grid.Column="0" Orientation="Horizontal" VerticalAlignment="Center"
+                    Margin="0,0,24,0">
+            <Button Background="Transparent" BorderThickness="0" Cursor="Hand"
+                    VerticalAlignment="Center" ToolTip="About LlamaCasty"
+                    Command="{Binding OpenAboutCommand}">
+                <Button.Template>
+                    <ControlTemplate TargetType="Button">
+                        <ContentPresenter/>
+                    </ControlTemplate>
+                </Button.Template>
+                <TextBlock FontSize="22" FontWeight="Bold" VerticalAlignment="Center">
+                    <Run Text="LlamaCas" Foreground="#e0e0e0"/><Run Text="ty" Foreground="#e94560"/><Run
+                        x:Name="BuildIdStamp" Text="{x:Static helpers:BuildStamp.Label}" FontSize="9"
+                        BaselineAlignment="Superscript" Foreground="#8888aa"
+                        ToolTipService.ToolTip="{x:Static helpers:BuildStamp.Label}"/><Run Text=" " FontSize="4"/>
+                </TextBlock>
+            </Button>
+            <!-- Settings gear (user directive): a couple characters beyond the brand,
+                 nudged right a couple more places 2026-09-22 (build 77 feedback).
+                 Moved up from the bottom bar — one menu: App Settings / Bug / Feature / About. -->
+            <Button Style="{StaticResource IconButton}" Margin="18,0,0,2" VerticalAlignment="Center"
+                    ToolTip="Menu" Click="GearButton_Click">
+                <Button.ContextMenu>
+                    <ContextMenu DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
+                        <MenuItem Header="App Settings" Command="{Binding OpenSettingsCommand}"/>
+                        <Separator/>
+                        <MenuItem Header="Report Bug" Command="{Binding OpenBugCommand}"/>
+                        <MenuItem Header="Feature Request" Command="{Binding OpenFeatureCommand}"/>
+                        <MenuItem Header="About" Command="{Binding OpenAboutCommand}"/>
+                    </ContextMenu>
+                </Button.ContextMenu>
+                <Path Data="M19.43,12.98c0.04,-0.32 0.07,-0.65 0.07,-0.98c0,-0.33 -0.03,-0.66 -0.07,-0.98l2.11,-1.65c0.19,-0.15 0.24,-0.42 0.12,-0.64l-2,-3.46c-0.12,-0.22 -0.38,-0.31 -0.61,-0.22l-2.49,1c-0.52,-0.4 -1.08,-0.73 -1.69,-0.98l-0.38,-2.65C14.46,2.18 14.25,2 14,2h-4c-0.25,0 -0.46,0.18 -0.49,0.42l-0.38,2.65c-0.61,0.25 -1.17,0.59 -1.69,0.98l-2.49,-1c-0.23,-0.09 -0.49,0 -0.61,0.22l-2,3.46c-0.13,0.22 -0.07,0.49 0.12,0.64l2.11,1.65c-0.04,0.32 -0.07,0.65 -0.07,0.98c0,0.33 0.03,0.66 0.07,0.98l-2.11,1.65c-0.19,0.15 -0.24,0.42 -0.12,0.64l2,3.46c0.12,0.22 0.38,0.31 0.61,0.22l2.49,-1c0.52,0.4 1.08,0.73 1.69,0.98l0.38,2.65c0.03,0.24 0.24,0.42 0.49,0.42h4c0.25,0 0.46,-0.18 0.49,-0.42l0.38,-2.65c0.61,-0.25 1.17,-0.59 1.69,-0.98l2.49,1c0.23,0.09 0.49,0 0.61,-0.22l2,-3.46c0.12,-0.22 0.07,-0.49 -0.12,-0.64L19.43,12.98zM12,15.5c-1.93,0 -3.5,-1.57 -3.5,-3.5c0,-1.93 1.57,-3.5 3.5,-3.5c1.93,0 3.5,1.57 3.5,3.5C15.5,13.93 13.93,15.5 12,15.5z"
+                      Fill="#a0a0b0" Width="18" Height="18" Stretch="Uniform"/>
+            </Button>
+        </StackPanel>
+
+        <!-- Session surface (top bar redesign): the bar is ONE surface rendered by
+             the FIRST decision — Record or Stream. Each world is the whole bar; the
+             other world never exists on screen. While running, the bar drops to a
+             reality line + End so nothing mid-session can be re-armed. -->
+        <StackPanel Grid.Column="1" Orientation="Horizontal"
+                    HorizontalAlignment="Center" VerticalAlignment="Center">
+            <!-- EDIT: explicit toggle. Blue = off (chat), orange = on (layers/properties). -->
+            <ToggleButton IsChecked="{Binding EditingActive, Mode=TwoWay}" Content="EDIT"
+                          Cursor="Hand" Height="32" Padding="14,0" Margin="0,0,24,0" VerticalAlignment="Center"
+                          FontWeight="Bold" FontSize="12" Foreground="#0b1326" BorderThickness="0">
+                <ToggleButton.Template>
+                    <ControlTemplate TargetType="ToggleButton">
+                        <Border x:Name="EditBody" Background="#38bdf8" CornerRadius="4" Padding="{TemplateBinding Padding}">
+                            <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                        </Border>
+                        <ControlTemplate.Triggers>
+                            <Trigger Property="IsChecked" Value="True">
+                                <Setter TargetName="EditBody" Property="Background" Value="#ff8c3a"/>
+                            </Trigger>
+                        </ControlTemplate.Triggers>
+                    </ControlTemplate>
+                </ToggleButton.Template>
+            </ToggleButton>
+            <!-- IDLE: the mode switch + the action(s) of the armed world. The three
+                 controls share one height (build 77 feedback) so they read as one
+                 family — segments host, Start/Go Live, and Test all sit at 32. -->
+            <StackPanel Orientation="Horizontal"
+                        Visibility="{Binding ShowIdleWorld, Converter={StaticResource BoolToVis}}">
+                <Border Background="#0f1622" CornerRadius="4" Padding="2" Height="32" VerticalAlignment="Center">
+                    <StackPanel Orientation="Horizontal">
+                        <ToggleButton Style="{StaticResource SegmentToggle}"
+                                      IsChecked="{Binding RecordPillOn}">
+                            <TextBlock Text="REC" Style="{StaticResource SegmentLabel}"/>
+                        </ToggleButton>
+                        <ToggleButton Style="{StaticResource SegmentToggle}"
+                                      IsChecked="{Binding OnAirPillOn}">
+                            <TextBlock Text="ON-AIR" Style="{StaticResource SegmentLabel}"/>
+                        </ToggleButton>
+                    </StackPanel>
+                </Border>
+                <!-- Go face names the world: "Start Recording" vs "Go Live".
+                     (Signed-out ON-AIR Start routes to the sign-in — StartSession.) -->
+                <Button Content="{Binding PrimaryStartButtonLabel}" Style="{StaticResource YtButton}"
+                        Height="32" Margin="10,0,0,0" Command="{Binding StartStreamCommand}"
+                        Visibility="{Binding ShowPrimaryStartButton, Converter={StaticResource BoolToVis}}"/>
+                <!-- Test is a child of Stream — a dry-run of the livestream, so it
+                     exists only inside the Stream world (stream armed + signed in). -->
+                <Button Content="Test" Style="{StaticResource YtButtonSecondary}" Padding="12,4" FontSize="11"
+                        Height="32" Margin="8,0,0,0" VerticalAlignment="Center"
+                        Command="{Binding StartTestCommand}"
+                        ToolTip="Run a private test broadcast to check your chat overlay."
+                        Visibility="{Binding ShowTestButton, Converter={StaticResource BoolToVis}}"/>
+            </StackPanel>
+
+            <!-- RUNNING: one reality line (dot + word + elapsed) and the stop -->
+            <StackPanel Orientation="Horizontal"
+                        Visibility="{Binding RunningVisible, Converter={StaticResource BoolToVis}}">
+                <Ellipse Width="12" Height="12" VerticalAlignment="Center"
+                         Fill="{Binding RunningDotBrush}"/>
+                <TextBlock Text="{Binding RunningText}" FontSize="16" FontWeight="Bold"
+                           Foreground="White" Margin="8,0,0,0" VerticalAlignment="Center"/>
+                <TextBlock Text="{Binding LiveElapsedText}" Foreground="White" FontSize="14"
+                           FontFamily="Consolas" VerticalAlignment="Center" Margin="8,0,0,0"/>
+                <Button Content="{Binding EndButtonText}" Style="{StaticResource YtButton}"
+                        Background="#333" Margin="14,0,0,0" Command="{Binding EndStreamCommand}"/>
+            </StackPanel>
+        </StackPanel>
+
+        <!-- Account zone: lives only in the Stream world. Signed out → Sign In;
+             signed in → a big avatar of the streaming account (build 77 feedback:
+             "make the user icon much bigger"). Record world has no YouTube
+             identity at all. -->
+        <StackPanel Grid.Column="2" Orientation="Horizontal" VerticalAlignment="Center">
+            <Button Content="Sign In" Style="{StaticResource YtButtonSecondary}"
+                    Margin="0,0,8,0" Command="{Binding SignInCommand}"
+                    ToolTip="Sign in to YouTube to go live."
+                    Visibility="{Binding ShowSignInButton, Converter={StaticResource BoolToVis}}"/>
+            <Button Style="{StaticResource IconButton}" Margin="0,0,0,0"
+                    ToolTip="{Binding AccountDisplayName}"
+                    Visibility="{Binding ShowAvatarButton, Converter={StaticResource BoolToVis}}">
+                <Button.ContextMenu>
+                    <ContextMenu>
+                        <MenuItem Header="Change Account" Command="{Binding ChangeAccountCommand}"/>
+                        <Separator/>
+                        <MenuItem Header="Logout" Command="{Binding LogoutCommand}"/>
+                    </ContextMenu>
+                </Button.ContextMenu>
+                <Border Width="40" Height="40" CornerRadius="20" Background="#16213e"
+                        ClipToBounds="True" BorderBrush="#3a4a66" BorderThickness="1">
+                    <Grid>
+                        <Image x:Name="AvatarImage" Stretch="UniformToFill"/>
+                        <TextBlock x:Name="AvatarInitial" Foreground="#e0e0e0" FontSize="20"
+                                   FontWeight="Bold" HorizontalAlignment="Center" VerticalAlignment="Center"
+                                   Visibility="Collapsed"/>
+                    </Grid>
+                </Border>
+            </Button>
+        </StackPanel>
+    </Grid>
+</UserControl>

Controls/TopBar.xaml.cs

@@ -0,0 +1,85 @@
+using System;
+using System.IO;
+using System.Net.Http;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media.Imaging;
+using ytLive.Helpers;
+using ytLive.ViewModels;
+
+namespace ytLive.Controls;
+
+public partial class TopBar : UserControl
+{
+    private static readonly HttpClient AvatarHttp = new() { Timeout = TimeSpan.FromSeconds(15) };
+    private string? _loadedAvatarUrl;
+
+    public TopBar()
+    {
+        InitializeComponent();
+        AvatarImage.Source = null;
+        AvatarInitial.Visibility = System.Windows.Visibility.Collapsed;
+    }
+
+    public void RefreshAvatar()
+    {
+        _ = LoadAvatarImageAsync();
+    }
+
+    private void GearButton_Click(object sender, RoutedEventArgs e)
+    {
+        // One menu (Settings / Bug / Feature / About), opened on click — moved up
+        // from the bottom bar so app-level actions live next to the brand.
+        if (sender is Button { ContextMenu: { } menu } button)
+        {
+            menu.PlacementTarget = button;
+            menu.Placement = System.Windows.Controls.Primitives.PlacementMode.Bottom;
+            menu.IsOpen = true;
+        }
+    }
+
+    private async System.Threading.Tasks.Task LoadAvatarImageAsync()
+    {
+        var vm = DataContext as MainViewModel;
+        var url = vm?.AccountAvatarUrl;
+        if (vm is not { IsConnected: true })
+        {
+            ShowAvatarFallback(null);
+            return;
+        }
+        if (string.IsNullOrWhiteSpace(url))
+        {
+            AppLog.Write("Avatar: connected but no profile image URL on the session");
+            ShowAvatarFallback(null);
+            return;
+        }
+        if (url == _loadedAvatarUrl && AvatarImage.Source != null) return;
+        try
+        {
+            var bytes = await AvatarHttp.GetByteArrayAsync(url);
+            using var ms = new MemoryStream(bytes);
+            var bitmap = new BitmapImage();
+            bitmap.BeginInit();
+            bitmap.CacheOption = BitmapCacheOption.OnLoad;
+            bitmap.StreamSource = ms;
+            bitmap.EndInit();
+            bitmap.Freeze();
+            _loadedAvatarUrl = url;
+            AvatarImage.Source = bitmap;
+            AvatarInitial.Visibility = System.Windows.Visibility.Collapsed;
+        }
+        catch (Exception ex)
+        {
+            AppLog.Write($"Avatar load failed ({url}): {ex.Message}");
+            ShowAvatarFallback(vm?.AccountDisplayName);
+        }
+    }
+
+    private void ShowAvatarFallback(string? name)
+    {
+        _loadedAvatarUrl = null;
+        AvatarImage.Source = null;
+        AvatarInitial.Text = string.IsNullOrWhiteSpace(name) ? "?" : name.Substring(0, 1).ToUpperInvariant();
+        AvatarInitial.Visibility = System.Windows.Visibility.Visible;
+    }
+}

Controls/index.md

@@ -0,0 +1,61 @@
+# Controls — index
+
+The phase-2 carved pieces of what used to be one monolithic `MainWindow.xaml`
+(1,681 lines → a 123-line shell). Each is a `UserControl` in the `ytLive.Controls`
+namespace, extracted one roll-back commit at a time (refactor-commit-12..18).
+See [`schema.md`](../schema.md) for the memory-map conventions.
+
+| File | Purpose |
+|------|---------|
+| `BottomBar.xaml(.cs)` | Footer (Row 3): stream stats (bitrate/fps/dropped/duration/health), resolution dropdown (gear menu moved up to TopBar 2026-09-22) |
+| `HealthBanner.xaml(.cs)` | Row 1 status banner + the 7 value→visibility converters live in the app theme, not here |
+| `TopBar.xaml(.cs)` | Row 0 session surface (2026-09-22 redesign): brand + gear menu (left), one segmented REC|ON-AIR mode switch + world actions (Record: Start Recording · Stream: Go Live + Test) + reality line while running (dot/word/elapsed) + End (center), account zone — Sign In or avatar w/ Change Account/Logout context menu (right). `RefreshAvatar()`, `GearButton_Click` |
+| `PreviewPane.xaml(.cs)` | Row 1 Col 1 center: the 1920×1080 `OverlayCanvas`/`SelectionOverlay`/`BrandFlashLayer`/`SocialBarElement`, text pull-out drawer, and the live-controls row (TRAX / game / mic meters + sliders + speakers + socials). **TASK 57:** dragging a webcam under the vertical tier routes through `MainViewModel.MoveWebcamInVerticalTier` (the six-spot snap inside the cropped band) instead of free-floating over the master, and a resize re-snaps the tile onto its spot (TASK 57 Unit 2: the resize routes through `MainViewModel.ResizeWebcamInVerticalTier` — the Chat camera's two sizes, then the snap) |
+| `SceneThumbnailStrip.xaml(.cs)` | Row 0 scene-picker strip (`ItemsControl` over `Scenes`), staged-red / live-green border highlight |
+| `LeftPanel.xaml(.cs)` | Row 1 Col 0 left panel: edit mode → layers+properties; live → YouTube chat. Source add/edit/remove, list drag-to-reorder, snapshot revert-accept. **TASK 51:** the webcam properties carry the Background section — `RemoveBackgroundPill` / `BlurBackgroundPill` (`PillToggle`, radio-exclusive via `WebcamSceneConfig.RemoveBackground`/`BlurBackground`) + `BackgroundStrengthSlider` (0..1, 5% snaps, shown only while an effect is on). **TASK 57:** the webcam properties carry a Geometry section (X/Y/W/H) — manual placement of the camera, bound to the **live** placement (the one the current tier shows), gated on `IsWebcamSelected` (not `SelectedElement.IsWebcam` — the TASK 51 test finds that panel by binding text and would match twice); the Shape button's `Visibility` is bound to `CanToggleClipShape`, so the circle option is NOT OFFERED in the vertical Chat layout. **TASK 58:** every drop-down, check box and field in the properties panel carries the theme's style (`YtComboBox`/`YtCheckBox`/`YtTextBoxCompact`) and paints no colour of its own — the guard is `ytLive.Tests/PropertiesStyleTests.cs`. **TASK 59:** the webcam's properties are a HIERARCHY — a `Shape` title owns the mirror switch and the shape choice (`Rect` | `Circle` as two `SegmentToggle` options, Rect selected by default, the circle option hidden where `CanToggleClipShape` is false), and every titled block (Geometry, Border Color, Border Thickness, Background) owns its content one indent deeper (Strength sits under Blur). **TASK 60:** the border-colour drop-down builds its menu from `Models/BorderColorPalette.cs` — each row is the hex plus the colour's NAME (`#e94560  Crimson`, tooltip "Crimson (#e94560)"); the swatch icon is unchanged. **TASK 61:** the four geometry fields (X/Y/W/H) share one fixed width (44px — the largest value, 1920, plus a sign) and their rows set `LastChildFill="False"`, so Y/H no longer stretch to fill the row. **TASK 62:** the border-colour field shows the palette's name beside the hex (`SelectedElement.BorderColorName`, empty for a custom hex) and keeps a fixed width so the name stays next to the hex. **TASK 63:** the border colour is picked with the **app's own drop-down** (`YtComboBox`) — the `...` button and its code-built `ContextMenu` are gone; the closed box shows the swatch + the colour's NAME, the rows show swatch + hex + name (the panel's own `DataTemplate`s + `Helpers/ClosedBoxTemplateSelector.cs`), and the hex field stays for a custom colour; `IsDescendantOf` falls back to `LogicalTreeHelper.GetParent` / `TemplatedParent` when `VisualTreeHelper.GetParent` returns `null` (at `PopupRoot`) so clicking a popup row does not trigger `MainWindow`'s deselection guard |
+| `OverlayHost.xaml(.cs)` | Root-grid overlay dialogs: Settings / Report Bug / Feature Request / About (+ licenses + license-key entry). `BackToAbout_Click` lives here |
+| `SceneThumbnailStrip.xaml.cs` | Code-behind for the strip above |
+| `LeftPanel.xaml.cs` | Code-behind for the panel above |
+
+## Window ↔ control contract
+
+The shell (`MainWindow.xaml(.cs)`) wires up each control and routes the few
+cross-cutting calls through it:
+
+- Ctor finds each control by `x:Name` (`TopBar`, `PreviewPane`, `LeftPanel`)
+  AFTER `InitializeComponent`, **before** any method touches it (null-ref guard).
+- `_previewPane.IsClickInsidePreview/Drawer` + `_leftPanel.IsClickInside` →
+  deselection guard in `Window_PreviewMouseLeftButtonDown`.
+- `_previewPane.UpdateSelectionOverlay(bool)` + `_leftPanel.OnSelectionChanged(vm)`
+  → selection/edit-mode routing from the VM's `SelectedElement` change.
+- `_topBar.RefreshAvatar()` on `IsConnected`/`AccountAvatarUrl` change.
+- Handlers in moved controls cast `(DataContext as MainViewModel)` — controls
+  inherit the window's DataContext; never pass the VM through a property.
+
+## Gotchas learned the hard way
+
+- **A UserControl cannot see `Window.Resources`** (StaticResource resolves by
+  element lookup, so it stops at the control boundary). The 7 converters
+  (`BoolToVis`, `InverseBoolToVis`, `NotNullToVis`, `NullToVis`, `HiddenBoolToVis`,
+  `EnumToBool`, `AllTrueToVis`) were promoted from `MainWindow.Resources` into
+  `Themes/Controls.xaml` (see [`Themes/index.md`](../Themes/index.md)).
+- **Moved XAML can lose its namespace**: a block cut from MainWindow carries no
+  root xmlns, so any `models:`/`Helpers:` ref in it breaks the build with
+  `MC2000: Value cannot be null (key)`. Declare `xmlns:models` / `xmlns:Helpers`
+  on each control's root (LeftPanel hit this).
+- **Name-looked-up host stubs must stay in the window**, not a control:
+  `WebViewHostPanel` (ctor `InitWebView2(WebViewHostPanel)`) and `ToastArea`
+  (`NotificationService.InArea("ToastArea")`) are resolved by name from the
+  window root — so `OverlayHost` deliberately leaves them as thin window-root
+  children (Commit 18). Since the 2026-09-14 composition-capture redesign only
+  `ToastArea` remains — `WebViewHostPanel` is deleted (web sources no longer
+  host a multiline XAML control; `InitWebView2()` runs from `MainWindow_Loaded`
+  with no panel argument).
+- When cutting visual wrappers, don't drop the outer `Border`'s
+  background/glow/margin — Commit 15 initially lost the preview's outer border
+  and had to restore it same-commit.
+
+Related: [`ViewModels/index.md`](../ViewModels/index.md) (MainViewModel the
+controls bind to), [`Themes/index.md`](../Themes/index.md) (styles/converters),
+[`Helpers/index.md`](../Helpers/index.md) (ViewModelBase, converters), the
+`MainWindow.xaml` shell at repo root that hosts these.

DESIGN.md

@@ -0,0 +1,67 @@
+# DESIGN.md — LlamaCasty visual design tokens (redesign exploration)
+
+> Source: Google Stitch export, 2026-10-26, from the proposed edit-screen mockup. Colors and type
+> only — no layout decisions are captured here. This is a design reference for the UX redesign
+> in progress; it is not yet wired into the app's theme (`Themes/Controls.xaml`).
+
+## Color
+
+### Surfaces (dark navy scale, darkest to lightest)
+
+| Token | Hex | Use |
+|---|---|---|
+| `background` | `#0b1326` | App window background |
+| `surface-container-lowest` | `#060e20` | Deepest recess (scene strip background, canvas housing) |
+| `surface-container-low` | `#131b2e` | Panel background (sidebars, headers) |
+| `surface-container` | `#171f33` | Card / grouped-section background |
+| `surface-container-high` | `#222a3d` | Hover state, input fields |
+| `surface-container-highest` | `#2d3449` | Selected/active row background |
+| `surface-bright` | `#31394d` | Lightest surface, rare use (strong hover) |
+| `outline` | `#334155` | Borders, dividers |
+| `outline-variant` | `#1e293b` | Subtle dividers, inactive VU meter segments |
+
+### Text
+
+| Token | Hex | Use |
+|---|---|---|
+| `on-surface` | `#dae2fd` | Primary text |
+| `on-surface-variant` | `#94a3b8` | Secondary / label text |
+
+### Accent — one role each, never mixed
+
+| Token | Hex | Role |
+|---|---|---|
+| `tertiary` (electric blue) | `#38bdf8` | The one interactive accent: selection, focus, sliders, primary buttons, transform handles |
+| `primary` (red) | `#ff5451` | **Reserved for on-air/recording state only** — LIVE badge, program border, End/Go Live |
+| `primary-container` | `#b91a24` | Red pressed/hover state |
+| `secondary` (amber) | `#ffb95f` | Game audio channel, Super Chat highlight |
+| `secondary-container` | `#ee9800` | Amber pressed/hover state |
+| `error` | `#ef4444` | Error states only (distinct from the on-air red) |
+
+**Rule carried from the critique sessions:** red must mean "live or recording" and nothing else.
+Don't reuse it for a Send button, a delete action, or any other control — that was the defect in
+the first Stitch draft of the live screen.
+
+## Typography
+
+| Token | Family | Use |
+|---|---|---|
+| `sans` | Inter (400/500/600/700) | All UI text — labels, buttons, panel titles |
+| `mono` | JetBrains Mono (500/600) | All numeric/telemetry values — bitrate, FPS, dB, coordinates, timers. Keeps digits from shifting width as values change. |
+
+Icons: Material Symbols Outlined.
+
+## Color roles (decided 2026-10-26)
+
+- **Red `#ff5451`:** YouTube references, on-air/GO LIVE, and record only.
+- **Attention orange `#ff8c3a`:** dropped packets, the live screen indicator, and blinking warning lights.
+- **Amber `#ffb95f`:** game audio and Super Chat only.
+- **`error` `#ef4444`:** unchanged for now; it sits close to the on-air red and may need revisiting.
+
+## Open questions for the next pass
+
+- These tokens have not been reconciled against the app's current WPF theme
+  (`Themes/Controls.xaml`). That comparison should happen once the redesign direction is locked,
+  not before — do not retrofit the current theme to these values yet.
+- No elevation/shadow scale, corner-radius scale, or spacing scale has been captured yet. Add them
+  here as they're decided, rather than letting them live only in Stitch exports.

Distribution.md

@@ -1,12 +1,42 @@
 # Distribution & IP Protection Plan
 
-> 360-degree protection strategy for LlamaCasty (.NET 8 / WPF), built around Polar.sh.
+> 360-degree protection strategy for LlamaCasty (.NET 8 / WPF).
+
+> ## ⛔ SUPERSEDED IN PART — 2026-09-27
+>
+> **Distribution is now the Microsoft Store: MSIX package + Store IAP.** The creator's criteria
+> were *"zero headaches, minimal maintenance (for me) while still providing accountability and
+> a reasonably easy upgrade flow"*, and that ruling deleted this document's central premise.
+>
+> **What still stands below:** §1 (code architecture / IP protection), §5 (obfuscation posture),
+> §6 (legal), §7 (hardening) — those are about protecting the *binary*, and an MSIX package is
+> still a binary. **§1.2's build-posture ceiling (HARDENED + MOCK_REWARDS, additive-only)
+> remains the agreed ceiling.**
+>
+> **What is dead:**
+> - **Polar as the distribution backbone** — the entire section below. Store IAP handles
+>   checkout, entitlements, refunds, tax, and the customer portal. So does **file hosting**:
+>   the Store is the delivery mechanism, so "upload `LlamaCasty.exe` to Polar as a File
+>   Download benefit" (§2) no longer exists as a step.
+> - **Code signing as our problem** — MSIX is signed by **Microsoft**. There is no certificate
+>   to buy, no HSM, no annual renewal. See §4.3, which was already corrected to say this, and
+>   `TASKS/research-store-certification.md` §2–3.
+> - **Velopack / the update URL / the DO droplet** — Store auto-update.
+>
+> **The authoritative plan is now [`TASKS/task-48-distribution-msix.md`](TASKS/task-48-distribution-msix.md).**
+> Keep this file for the protection sections; do not re-derive a delivery strategy from it.
 
 ---
 
-## Polar.sh as the Distribution Backbone
+## Polar.sh as the Distribution Backbone — ⛔ OBSOLETE (2026-09-27)
 
-Polar handles everything between "customer wants to pay" and "customer has a working license key." We don't build any of that. What Polar gives us:
+> **Historical record only.** Retained because the fee tables and the reasoning about *why*
+> one-time beat subscription were worth working out. **None of the "How We Use It" rows are
+> current**, with one exception worth keeping: the Merchant-of-Record point — *someone else
+> collects and remits VAT/GST* — is still true under Store IAP, because **Microsoft** is now
+> that someone. That fact alone was the strongest argument for the ruling.
+
+Polar handled everything between "customer wants to pay" and "customer has a working license key." We didn't build any of that. What Polar *was* going to give us:
 
 | Capability | How We Use It |
 |------------|---------------|
@@ -14,13 +44,15 @@ Polar handles everything between "customer wants to pay" and "customer has a wor
 | **File hosting** (up to 10GB) | Upload `LlamaCasty.exe` (self-contained, ~80-120MB) as a "File Download" benefit. Customers get signed, personal download URLs. SHA-256 checksums included. |
 | **Checkout** | Polar's hosted checkout page handles payment. No Stripe integration, no PCI scope, no custom checkout UI. |
 | **Customer portal** | Customers self-serve: view/copy license keys, see expiry, deactivate devices, rotate compromised keys. We don't build a portal. |
-| **Subscriptions** | If we go subscription model (deferred), Polar handles recurring billing, dunning, cancellation. |
+| **One-time orders** | **Chosen model (2026-09-21):** perpetual license via a one-time Polar order — no subscription. Polar also supports recurring billing if ever needed, but we do not use it. |
 | **Merchant of Record** | Polar collects and remits VAT/GST/sales tax globally. We never touch tax compliance. |
 | **Webhooks** | Polar notifies our backend on purchase, cancellation, key rotation. Used for optional telemetry (section 6.3). |
 
-**Polar pricing (2026):** 5% + $0.50 per transaction (Starter plan). No monthly fee.
+**Polar pricing (2026):** 5% + $0.50 per transaction (Starter plan). No monthly fee. ⛔ *No
+longer paid to anyone — the equivalent cost is now inside the Store revenue share, whose rate
+is unverified (see `TASKS/research-store-certification.md` §11).*
 
-**What Polar does NOT handle:** Obfuscation, code signing, anti-tamper, runtime protection, EULA, DMCA. That's all us — sections 1-3, 5-7 below.
+**What Polar did NOT handle:** Obfuscation, code signing, anti-tamper, runtime protection, EULA, DMCA. That's all us — sections 1-3, 5-7 below.
 
 ---
 
@@ -273,24 +305,34 @@ steps:
 ### 4.1 Files to Ship
 
 ```
-LlamaCasty.exe          (single-file, self-contained, ~80-120MB)
+LlamaCasty.msix         (full-trust x64 package, self-contained, ~159MB)
 ```
 
-Single-file means everything is inside the `.exe`. No DLLs, no runtime dependency.
+Built by **`scripts/package-msix.sh`** (TASK 48 item 2, shipped 2026-10-22): it publishes
+`Release -r win-x64 --self-contained` into `artifacts/msix-stage`, stages
+`Packaging/Package.appxmanifest` (as `AppxManifest.xml`) + `Packaging/Assets/`, and packs with
+the Windows SDK's `makeappx` → `artifacts/LlamaCasty.msix` (gitignored). Unsigned by default —
+**the Store signs submissions**; set `MSIX_PFX`/`MSIX_PFX_PASSWORD` to sign a package for a
+local test install. The manifest is a full-trust `packagedClassicApp` at `mediumIL` with
+`runFullTrust` + webcam + microphone (see `TASKS/task-48-distribution-msix.md` item 2).
 
-**Why not an installer?**
-- Single `.exe` is simpler to distribute and update.
-- No admin rights required (installs to `%LOCALAPPDATA%`).
-- No installer framework to maintain (WiX, Inno Setup, etc.).
-- User drops it anywhere and runs it.
+A single-file `.exe` is **no longer the artifact**: the Store needs a package, and the package
+carries the runtime (~80-120MB of it) plus the bundled ffmpeg (~135MB of DLLs). No installer
+framework and no admin rights — the Store handles install, update and uninstall.
 
-**Caveat:** Self-contained single-file means ~80-120MB due to bundled .NET runtime. For smaller size, use framework-dependent publishing (requires .NET 8 runtime on user machines) — drops to ~5-10MB.
+### 4.2 Distribution via Polar — ⛔ OBSOLETE (2026-09-27)
 
-### 4.2 Distribution via Polar
+> **Superseded by Microsoft Store MSIX + Store IAP** (ruling in
+> `TASKS/task-48-distribution-msix.md` item 0). The Store re-signs, hosts, updates, and takes
+> payment — so file hosting, license keys, checkout, the customer portal, device deactivation and
+> key rotation are **all** handled by Microsoft and none of it needs building. Retained below as a
+> record of the model that was designed and abandoned. ⚠️ **The `$29`/`$49` one-time prices in this
+> section are dead** — the settled pricing is **`$10/mo` or `$400` lifetime**, net of a verified
+> 15% Store share.
 
-**Product setup on Polar:**
+**Product setup on Polar (as designed, never shipped):**
 
-1. Create a product: "LlamaCasty" — one-time purchase (or subscription if deferred).
+1. Create a product: "LlamaCasty" — **one-time purchase** (perpetual license; $29 founder / $49 list).
 2. Add two benefits:
    - **License Key** — brandable prefix `LLAMA-****`, activation limit (e.g., 3 devices), optional expiry.
    - **File Download** — upload the signed `LlamaCasty.exe` (~80-120MB). Polar generates signed, personal download URLs. SHA-256 checksum included.
@@ -313,9 +355,43 @@ Single-file means everything is inside the `.exe`. No DLLs, no runtime dependenc
 - If a key is compromised, customer or merchant can rotate it via Polar.
 - Previous key stops validating immediately. Status, usage, limits, expiry preserved.
 
+**What the Store does instead:** the customer installs from the Store listing, pays through Store
+checkout, and the app reads the entitlement the OS already holds. There is no key to enter, no
+activation call, no portal to visit, and no offline-grace period to maintain — which also retires
+the whole "network flaky → app thinks I'm expired" bug class in §4.5.
+
 ### 4.3 Code Signing
 
-**Certificate:** Buy an EV (Extended Validation) code-signing certificate from DigiCert or Sectigo ($200-400/year). EV certificates get instant SmartScreen reputation; DV/OV certs trigger SmartScreen warnings for months.
+> ⚠️ **The cert choice below is a live decision, and the old plan's EV recommendation is
+> dead.** Microsoft **removed the SmartScreen instant-bypass for EV certificates in March
+> 2024** — an EV-signed file now accrues reputation exactly like an OV-signed one, so paying
+> $400+/yr buys precisely what paying ~$150 buys. **Do not buy EV.**
+>
+> **But the more interesting finding is that you may not need a certificate at all.** Three
+> costs, current as of 2026-09-27:
+>
+> | Route | Cert/yr | SmartScreen | Note |
+> |---|---|---|---|
+> | **Microsoft Store (MSIX)** | **$0** — Microsoft re-signs | **No warning** | Requires MSIX packaging; Store review; public listing |
+> | **Microsoft Store (EXE/MSI)** | $120–300 — *your* cert | Warning ramp | Store does **not** re-sign; silent install mandatory. Strictly dominated — cert required anyway |
+> | **Direct + OV cert** | $150–300 | Warning ramp | Worldwide availability |
+> | **Direct + Azure Artifact Signing** | ~$9.99/mo ≈ $120 | Warning ramp | **Individuals: USA/Canada only.** Identity validation required |
+>
+> Signing does **not** clear the warning on day one either way: a valid cert stops the
+> *malware* warning immediately, but "unrecognized publisher" clears as SmartScreen accrues
+> reputation from real download volume. Budget cert validity at **460 days** (CA/B Forum
+> CSC-31) — this is a recurring line item, not a one-time purchase — and note that private
+> keys must sit on an **HSM or hardware token**.
+>
+> **The full comparison, the four real combinations, and the policy analysis live in
+> [`TASKS/research-store-certification.md`](TASKS/research-store-certification.md) §2–3.
+> The executable checklist is [`TASKS/task-48-distribution-msix.md`](TASKS/task-48-distribution-msix.md),
+> and the route decision is the creator's.**
+
+**Certificate:** Buy an **OV (Organization Validation)** code-signing certificate from DigiCert
+or Sectigo (~$150–300/year), or an **Azure Artifact Signing** profile (~$9.99/month,
+USA/Canada individuals only) if the geography allows. ⛔ **Not EV** — no SmartScreen benefit
+since March 2024. **Or buy nothing at all** if the route is the Microsoft Store.
 
 **Signing process:**
 ```powershell
@@ -332,7 +408,15 @@ Set-AuthenticodeSignature -FilePath "LlamaCasty.exe" `
 
 **Storage:** Certificate `.pfx` file stored in GitHub Secrets (or Azure DevOps secure files). Never committed to the repo.
 
-### 4.4 Update Mechanism
+### 4.4 Update Mechanism — ⛔ OBSOLETE (2026-09-27)
+
+> **Superseded by Store updates.** Microsoft delivers and updates the app from the listing, so
+> there is nothing to check and no manifest to host. The Velopack updater that used to sit in
+> `App.xaml.cs` **downloaded *and executed***, which Store policy **10.2.2** does not permit — its
+> removal was a **compliance action**, not optional cleanup, and it is **done** (TASK 48 slice 3,
+> 2026-10-22: the package reference and the bootstrap are gone; `ytLive.Tests/StorePackagingTests.cs`
+> guards it). The Polar-native design below is retained as a record of the approach that was
+> rejected; it is not an option.
 
 **Polar-native approach (no custom infrastructure):**
 
@@ -367,10 +451,18 @@ public class UpdateCheckService
 - Download link points to Polar's customer portal (not direct download).
 - This adds one external dependency (GitHub) but keeps Polar as the source of truth.
 
-### 4.5 Licensing Logic (already implemented)
+### 4.5 Licensing Logic — ⛔ BEING DELETED (2026-09-27)
+
+> ⚠️ **"Already implemented" was true as of 2026-09-21 and is no longer.** `PolarLicenseService`
+> and `Helpers/PolarLicense.cs` are being **removed** as part of the TASK 10 teardown (TASK 48 item 0).
+> Store IAP replaces the whole validation hop: `IsPremium` is derived from the **OS-supplied Store
+> entitlement**, so there is no network call, no key, and — importantly — **no 14-day offline-grace
+> machine to protect**, which retires the entire "network flaky → app thinks I'm expired" bug class.
+> What survives is only `IsPremium` → `BrandFlashEnabled = !value`. Retained below as the record of
+> what shipped and why it no longer applies.
 
 ```csharp
-// Services/PolarLicenseService.cs — already ships
+// Services/PolarLicenseService.cs — shipped under Polar; being deleted
 // Calls Polar's customer-portal validation endpoint (no auth required)
 // Survives obfuscation — property names excluded via [Obfuscation(Exclude = true)]
 [Obfuscation(Exclude = true)]
@@ -383,11 +475,11 @@ public class LicenseValidationResult
 }
 ```
 
-**What's already done:**
-- `PolarLicenseService` validates keys against Polar API.
-- `OrganizationId` is hardcoded (safe — it's public knowledge, tied to our Polar account).
-- License state persists in `LayoutStore.Settings` (SQLite) with offline grace period.
-- `PremiumUrl` points to Polar checkout.
+**What shipped under Polar (now being deleted):**
+- `PolarLicenseService` validated keys against the Polar API.
+- `OrganizationId` was hardcoded.
+- License state persisted in `LayoutStore.Settings` (SQLite) with an offline grace period.
+- `PremiumUrl` pointed to Polar checkout.
 
 **What survives obfuscation:** The validation logic in `Services.dll` is obfuscated. An attacker who decompiles the exe sees only the UI calling an interface — the actual Polar API call is in the obfuscated DLL.
 

HANDOFF.md

@@ -1,45 +1,378 @@
-# HANDOFF — Session State
+# HANDOFF — 2026-10-26 (ai.md memory split, 3 units landed; see below — everything after this block is the prior 2026-10-22 state, still accurate)
 
-## Branch / Commit State
+## At a glance (2026-10-26 docs session)
+- **`ai.md` is being split into `docs/ai/*.md`** (user-approved: verbatim move, staged units, "ai.md
+  only"). Three units landed as separate commits, **docs only, not pushed**:
+  `804b1d2` (frame pipeline: cadence/timing/budget/compositor/pump),
+  `096bf6d` (capture: backdrop/webcam/background effects/vertical tier),
+  `a4dfca6` (output: ffmpeg/encoder/recording/audio). Each move is byte-identical in the new file;
+  `ai.md` keeps a short stub with the load-bearing invariants + a link. `docs/ai/index.md` routes.
+  **`ai.md` is now 1,289 lines (~32k tokens), down from 2,702 (~64k)** — more than half the
+  mandatory-read cost is gone.
+- **Also landed (docs only, not pushed):** `ef60f1f` — distribution & packaging deferred until near
+  v1 (creator ruling 2026-10-26); see "Next step" below for the still-open route contradiction.
+- **Remaining split candidates in `ai.md`** (not yet moved — smaller, more interleaved with law that
+  should stay): Architecture's "Social bar" (46) + "Toast notifications" (24) + "Licensing — do not
+  violate" (60); "YouTube Live API — design constraints" incl. "Native events & alerts" (349 total,
+  99 of it alerts); "Monetization" (136); "Windows packaging & distribution" (135, frozen per the
+  deferral above). None of these is urgent — pick back up only if the user asks to continue the split.
+- **Scope-check passed on all three commits**; no source touched this session.
 
-**`main`**, working tree is **CLEAN** — all changes committed and pushed.
+---
 
-No feature branches pre-1.0: all work lands on `main` per work unit.
+## Prior state (2026-10-22) — the creator's properties-panel asks shipped, incl. TASK 63, and pushed; the vv webcam Units 1+2 state below
 
-**Latest commit:** `6031a56` — gear cleanup + Default Location for Recordings + single Start + socials hover glow.
+## At a glance
+- **Branch** main, tracking `origin/main`. **The six-commit properties-panel batch is PUSHED**
+  (2026-10-22, as a sub-milestone): TASK 58 the theme sweep, TASK 59 the properties hierarchy,
+  TASK 60 the colour names, a docs commit, TASK 61+62 the geometry field widths and the colour
+  name beside the hex, and TASK 63 the border-colour picker as the app's own drop-down — the
+  creator's properties-panel asks, done in one batch. `origin/main` is now `987fdda`.
+  - The vv feature (Units 1+2) **was** pushed at its close (2026-10-21 — the creator approved
+    the Unit 1 push after testing it, and the completed feature is a milestone).
+  - **The push path changed:** `origin` is now
+    `https://llgit.llamachile.tube/gramps/LlamaCasty.git` (HTTPS + the credential helper
+    `/home/gramps/bin/gitea-credential`, which reads the password from the gitignored
+    `CREDENTIALS.md`; plain `git push` works). The old SSH remote was broken twice over: the repo
+    was **renamed `gramps/ytLlive` → `gramps/LlamaCasty`**, and `llgit:2214` refuses the publickey
+    of this machine's key even though it IS registered (account key id 6 "Corsair VSC"). Ask the
+    Gitea REST API, don't do key archaeology — recipe in `MyMistakes.md` → 2026-10-21.
+- **This session shipped vv webcam Units 1+2** (the vertical 9:16 tier keeps its OWN camera placement
+  per scene; 16:9 restores the desktop layout exactly; the Chat scene in vv is rect-only and can be
+  enlarged to fill a whole 607×540 area). Code + memory in ONE commit each; the ONE Good Dog tests
+  are `ytLive.Tests/VerticalWebcamLayoutTests.cs` (Unit 1) and
+  `ytLive.Tests/VerticalChatCameraLayoutTests.cs` (Unit 2). **Only the creator's hands-on check is
+  left** — see the vv section.
+- **TASK 58 — the properties panel now wears the theme** (shipped 2026-10-21). The creator's
+  "why is the drop-down not in the same style as the others?" was a real defect: those drop-downs
+  (and every check box, and every properties field) had been hand-painted with a `Background`/
+  `Foreground` instead of a style, so WPF drew the **light system template** on top of the dark
+  panel. Now: `ComboBox` → `YtComboBox`, `CheckBox` → `YtCheckBox` (new), properties fields →
+  `YtTextBoxCompact` (new, BasedOn `YtTextBox`). Guard:
+  `ytLive.Tests/PropertiesStyleTests.cs`.
+- **TASK 59 — the properties panel is a hierarchy** (shipped 2026-10-21). A title owns its
+  content and the content is indented one level (10px): `Shape` (new title) over the
+  Mirror switch and the shape choice, the drag hint indented under that row, Geometry /
+  Border Color / Border Thickness as titles with their fields indented, Background's
+  Remove + Blur indented, and Strength one level deeper under Blur. **The shape became a
+  CHOICE**: `Rect` | `Circle` as two segment options with **Rect selected by default**
+  (the old single button showed the *next* action, "Round"). The mutual exclusion lives
+  in the model (`IsRectShape`/`IsRoundShape` on `SceneElement`) — a WPF `RadioButton`
+  group would kill the bindings. Guard: `ytLive.Tests/PropertiesHierarchyTests.cs`.
+- **TASK 60 — the border-colour drop-down names every colour** (shipped 2026-10-21). The creator:
+  *"the #hex values are good, but add a corresponding color name/label next to the value"* — each row
+  now reads `#e94560  Crimson` (the name dimmed, the tooltip "Crimson (#e94560)"). The 14 colours
+  moved out of the click handler into `Models/BorderColorPalette.cs` (`NamedColor(Hex, Name)` +
+  `NameOf(hex)`), so the list is testable and extensible. Guard:
+  `ytLive.Tests/BorderColorPaletteTests.cs`.
+- **TASK 61 + 62 — the geometry fields and the border-colour field** (shipped 2026-10-21).
+  - **61:** the X/Y/W/H fields share ONE fixed width (44px — the largest geometry value, 1920,
+    plus a sign) and their rows set `LastChildFill="False"`, so Y/H no longer stretch to fill
+    the row while X/W sized themselves to their text. Guard: `ytLive.Tests/GeometryFieldWidthTests.cs`
+    (it MEASURES the widest value with WPF's `FormattedText` — measure, don't guess).
+  - **62:** the border-colour field shows the palette's **name beside the hex**
+    (`SceneElement.BorderColorName`, empty for a custom hex), and the hex field keeps a fixed
+    width so the name stays next to the hex. The field stays editable (a custom hex can
+    still be typed). Guard: `ytLive.Tests/BorderColorNameTests.cs`.
+- **TASK 63 - the border-colour picker IS the app's drop-down** (shipped 2026-10-21; **popup click
+  deselection fixed 2026-10-22**). The creator:
+  *"why does the drop down under the web cam properties not show the same style for the border
+  color drop down list box?"* and *"we established look-and-feel standards. And yet you keep
+  ignoring these and I'm wondering why."* **Root cause of the miss:** the TASK 58 sweep looked for
+  control **types** (`ComboBox`/`CheckBox`/`TextBox`) without a theme style - and the border picker
+  was NONE of those: it was a `...` `Button` whose `Click` handler built a `ContextMenu` in code.
+  It was never in the sweep's scope, and `PropertiesStyleTests.cs` (a type-based guard) could not
+  see it either. Now: the picker is a **`YtComboBox`** bound to the palette
+  (`SelectedElement.BorderColorOptions` / `BorderColorEntry`), the **closed box shows the swatch +
+  the colour's NAME**, the **rows show swatch + hex + name**, the hex field stays for a custom
+  colour, the swatch is painted by the theme's `HexToBrush` converter, and the hand-built menu +
+  `WebcamBorderColorPicker_Click` are **gone**. The closed box != the rows only through
+  `Helpers/ClosedBoxTemplateSelector.cs` (WPF copies `ItemTemplate` into the read-only
+  `SelectionBoxItemTemplate`; the selector is told them apart by the `ContentPresenter`'s
+  templated parent - `ComboBox` = closed box, `ComboBoxItem` = a row). **2026-10-22 creator bug fix:**
+  clicking a colour in the open `ComboBox` popup registered as an exit from the properties listing
+  because `LeftPanel.IsDescendantOf` used `child is Visual ? VisualTreeHelper.GetParent(child) :
+  LogicalTreeHelper.GetParent(child)` — at `PopupRoot` (which IS a `Visual`),
+  `VisualTreeHelper.GetParent` returns `null`, so `IsDescendantOf` stopped without crossing
+  `PopupRoot`'s logical parent (`PART_Popup` → `ComboBox` → `ElementsScrollViewer`), and
+  `MainWindow.Window_PreviewMouseLeftButtonDown` cleared `SelectedElement = null`. Fixed by falling
+  back to `LogicalTreeHelper.GetParent` / `TemplatedParent` when `VisualTreeHelper.GetParent`
+  returns `null`. Guard: `ytLive.Tests/BorderColorPickerTests.cs` (model + panel + the **real
+  widget**, including `LeftPanel.IsClickInside` on an open popup row and clicking a row to change
+  `BorderColor`). The TASK 60
+  guard (`BorderColorPaletteTests`) was updated to guard the new wiring (the drop-down is bound to
+  the palette; no second list of colours anywhere).
+- **TASK 55 slice 1 — the log is capped (shipped 2026-10-22).** `startup.log` was uncapped (23 MB
+  and growing every few seconds — ffmpeg logs every stderr line). Now it rolls to `startup.1.log`
+  at 5 MB (one rolled copy kept), so the growth is bounded. The policy is
+  `Helpers/LogRotation.cs` (a pure function over a path — `AppLog`'s 156-call-site surface is
+  unchanged; the seams are two `internal` properties). Guard:
+  `ytLive.Tests/AppLogRotationTests.cs`. Slices 2 (temp alert-clip cleanup) and 3 (low-disk
+  guard before recording) are still open.
+- **TASK 48 slice 2 — the app PACKS as a Store MSIX (shipped 2026-10-22).** `Packaging/Package.appxmanifest`
+  (full trust: `Windows.FullTrustApplication` + `uap10:TrustLevel=mediumIL` +
+  `uap10:RuntimeBehavior=packagedClassicApp` + `rescap runFullTrust`, plus webcam/microphone
+  `DeviceCapability`s, x64, en-US only) + `Packaging/Assets/` (four logo tiles generated from the
+  app's own artwork by `scripts/make-store-logos.py`) + `scripts/package-msix.sh` (publish
+  `Release -r win-x64 --self-contained` → stage → `makeappx pack`, optional `MSIX_PFX` signing).
+  **First real package built: `artifacts/LlamaCasty.msix`, 159 MB, 509 files, `Package creation
+  succeeded`** (`artifacts/` is gitignored). Guard:
+  `StorePackagingTests.The_package_manifest_declares_full_trust_camera_and_microphone`.
+  ⚠️ Before submission the manifest's `Identity/@Publisher` and `PublisherDisplayName` must be
+  set to the exact values Partner Center shows — a mismatch is a rejection.
+- **TASK 48 slice 3 — the self-updater is gone (shipped 2026-10-22).** The Store route (creator
+  ruling 2026-09-27) means the Store updates the app, so the Velopack package + bootstrap were
+  **deleted** (`ytLive.csproj`, `App.xaml.cs`) — a compliance action, not cleanup: the updater
+  downloaded *and executed*, which Store policy 10.2.2 does not permit. The DO update-URL droplet
+  dies with it. Guard: `ytLive.Tests/StorePackagingTests.cs` (no updater package, no updater API
+  in any app source file). The app was smoke-tested after the removal: `MainWindow loaded`, no
+  exceptions. **Still open on TASK 48:** slice 2 (the `Package.appxmanifest` + packaging project),
+  slice 6 (the full-trust recording invariant comment), slice 7 (disqualifier re-check), slice 8
+  (the pre-submission gates) — and slices 4/5 are the creator's (Certification Kit, Partner
+  Center listing, the demo account).
+- **The previous session (HA lights) produced NO ytLive code** — it was spent on the creator's Home
+  Assistant light alert system (off-repo, `192.168.50.145`). See `MyMistakes.md` → 2026-10-21: the plan
+  was one tweak to a verified-working script; the script was rewritten twice, the alert path broke, and
+  the day was burned. **The HA work landed OK in the end** (recipes + measurements now in
+  `MyMistakes.md`). Records below so the next session does not re-hunt.
 
-## What's In Flight
+## HA light alert system — current, verified state (2026-10-21)
+Five Tapo bulbs: `light.br1`, `light.br2`, `light.officeone`, `light.officetwo`,
+`light.death_star_light`. Purpose: the creator is **deaf** — lights are the alert channel; the phone
+(`notify.mobile_app_mis_lx9`) is secondary. **The iPhone is gone — never notify it.**
 
-Nothing — clean tree, ready for next task.
+| State | br1 / officeone | br2 / officetwo | Death Star |
+|---|---|---|---|
+| Idle | off | off | off |
+| Pump running | off | **off** | **blue only** (creator directive) |
+| Leak | warm-white 100% | purple | purple |
+| Alarm | warm-white 100% | red | red |
+| Doorbell | green, 8s | green, 8s | green, 8s |
+| Doorbell during an alert | — | suppressed — | — |
+| Clear | off | off | off |
 
-## Landmines
+**Architecture:** `script.alerts_arm` / `alerts_clear` write only `input_text.light_alert`
+(`none|leak|alarm|motion`, restart-surviving). **`script.alerts_render_lights` is the single writer of
+the bulbs** — flat top-level `if`/`else` blocks (nested `if` and `choose:` both silently lit nothing;
+do not "improve" the shape). Priority: an alert always beats pump status.
 
-- **TextBox.Mode=OneWay** is required for `RecordFolderDisplay` binding (get-only computed property).
-- **Pre-existing test failures (do not chase):** `AudioPipelineTests.Mix_HonorsProviderGains…` +
-  `RoundClipInteractionTests.Round_Clip_Corner_Is_Grabbable…`.
-- **App running locks `ytLive.exe`** → build fails MSB3027. Kill PID before building.
-- **Test suite hangs** when running full vstest (WPF `RealAppHost` dispatcher deadlock); individual
-  tests pass in isolation. Use `dotnet test` on individual test classes, not the full suite DLL.
-- **Pre-commit gate:** `./scripts/verify.sh` — clean build (0 warnings) + full tests + scope check.
+**⛔ THE ENTITY-ID TRAP (cost this session hours):** the YAML key is `alerts_render` but the entity id is
+**`script.alerts_render_lights`**. `script.turn_on` on a non-existent entity returns **HTTP 200 and does
+nothing** — no error, no log. All callers now use the `_lights` id. Check this first on any "script does
+nothing" symptom.
 
-## Todo state
+**Pump status** is a *status*, not an alert (auto-clearing), and is keyed off
+`sensor.water_pump_current_consumption` — **never** `switch.water_pump_2`, which was observed latched
+`on` for hours at 0.0A draw and painted the bedroom blue at 5am.
 
-- TASK 3 (Capture Pipeline): 27/30 items done. Open: preview compositor (16), text source (17), alerts (20). Window capture absorbed into Screen picker (done). Background removal excluded from this build.
-- TASK 4 (RTMP Ingest): ✅ Shipped — all 7 items done (compositor, FFmpeg locator, encoder+RTMP, WASAPI audio, frame-pipeline, health stats, one-click go-live).
-- TASK 9 (Stream Management): items 1–3 shipped (reusable stream, health monitoring). Items 4–7 open: live chat, error handling, visibility picker, full broadcast form.
-- TASK 10 (Monetization): steps 1–7 shipped. Velopack auto-update pending.
-- TASK 18: shipped. Remaining = running-app verification (creator).
-- TASK 19/23 (Control Surface UX): ✅ Shipped — thumbnails, transitions (Cut/Fade/Move), edit mode, left panel two-state.
-- TASK 20 (Hotkeys): ✅ Shipped — F1-F5 scenes, F6-F9 actions, config UI, global hotkeys, conflict detection, persistence.
-- TASK 21 (Media source): Increment A shipped (model + persistence). Slices 4–12 open (decoder, FramePump wiring, compositor, loop/volume, UI, tests). Blocked on ffmpeg for integration test.
-- TASK 22 (Audio sync offset): not started — required for v1.
-- TASK 30: gear cleanup + record location + single Start + preview layout restructure — shipped across commits `6031a56` + `61b850f` + `455a409`.
-- Monetization: deferred (creator rethinking price/subscription model).
-- **File refactor (in progress — Commit 0 done):** MainViewModel.cs (3,900 lines) will be split into functional partials (Scenes, Background, Webcam, Audio, Trax, Socials, Streaming, Chat, Overlays, Account, License). `MainViewModel` is now `public partial class` (scaffold commit). Remaining: one commit per partial, each a roll-back point, `verify.sh` + `scope-check.sh` before each, docs in the same commit. MainWindow.xaml (1,681 lines) will be split into UserControls after Phase 1. Zero behavior change, tests stay green.
+**HA files touched** (`/config`, root-owned → writes need `sudo`): `scripts.yaml`, `automations.yaml`,
+`configuration.yaml` (added `input_text.light_alert` / `_prev`). Backups: `scripts.yaml.bak-alertbuild`,
+`automations.yaml.bak-alertbuild`, `automations.yaml.bak-notify-20261020`, `configuration.yaml.bak-tplinkfix`.
+Zombie entities deleted from the registry: `script.leak_strobe`, `script.doorbell_flash` (old one),
+`automation.leak_strobe_notify_clear_restore`, `script.alerts_render_lights_2`.
+**Leak sensor is healthy** (`binary_sensor.pump_leak_moisture` = off, battery 100, signal 3) — an earlier
+"unavailable" claim was a bad read during a reload; `alert_leak_on` now also triggers on the latched
+`sensor.pump_leak_last_water_leak_alert`.
 
-## Session summary (2026-08-29)
+## vv webcam feature — locked rules (creator, 2026-10-17) — **Units 1+2 shipped 2026-10-21**
+| mode | shape | size | position |
+|---|---|---|---|
+| 16:9 | as today | as today | as today |
+| **vv · Live** | **circle OR rect, creator's choice** | small tile | one of six spots: top/bottom × L/C/R |
+| **vv · Chat** | **rect only — no circle option** | normal, or enlarged to fill one area (607×540) | enlarged → top or bottom |
+| Starting / BRB / Ending | unchanged | unchanged | unchanged |
 
-- Corrected task status tracking: TASK 4 → ✅ Done, TASK 3 item15 (Window capture) → ✅ absorbed into Screen picker, TASK 3 status updated to 27/30
-- ai.md updated: TASK 4 steps 5-7 added as shipped, stale "frame-pipeline wiring follows" removed
-- HANDOFF.md todo state expanded with full statuses for all active tasks
-- Discussed file organization: MainViewModel.cs (3,900 lines) is a god-object with 49 commands mixing scenes, camera, audio, streaming, socials, overlays, and auth. Next session: split into functional partials
+- **Placement is set by tap/click-drag with snap, exactly like the socials today**, plus manual entry in
+  properties. **vv keeps its own camera position, size and shape per scene** — switching back to 16:9
+  restores the desktop layout exactly.
+- **No explicit borderless/no-background mode is needed** (round + border/bg options already allow it).
+- Creator's "square" means the rectangular view (the camera's own aspect), not a literal 1:1 box.
+
+### What the code already gives us (do not re-hunt)
+- **vv = the active tier's centred band crop.** 1080p60-vertical: master band **x 656.25–1263.75
+  (607.5 wide), full height**, upscaled to 1080×1920 (`MainViewModel.Streaming.cs` `ApplyStreamQuality`
+  → `OutputRect*`). The band splits into **two 607×540 areas** (top/bottom).
+- **The Live webcam sits at x≈1425 → entirely outside the band** — in vv it is invisible. That is the
+  whole motivation.
+- **Geometry only — no render-path change.** Preview (`Controls/PreviewPane.xaml` 144–230) and compositor
+  (`Services/Compositor/SceneCompositor.cs` 389–397) both read the element's own `X/Y/W/H` + `ClipShape`.
+- **Round / border / background are independent:** `ClipShape.Round`; `HasBorder` = width > 0 AND valid
+  6-hex colour; `BackgroundEffect` = None/Remove/Blur.
+- **Per-scene camera size policy exists**: `MaxWebcamWidthFor/HeightFor` (Chat 1358×764, others 960×540)
+  + `ClampWebcamToBounds`. **A 607×540 tile sits inside both → no clamp change.**
+- **Storage:** `WebcamSceneConfig` table; new columns via `MigrateWebcamConfigTable()` as idempotent
+  `ALTER TABLE … ADD COLUMN` guarded on `PRAGMA table_info` + `LayoutStore.Save.cs` INSERT and
+  `LayoutStore.Load.cs` SELECT.
+- **Precedent for remembered geometry:** `RectWidth/RectHeight` + `ToggleClipShape`
+  (`Models/SceneElement.cs` 124–152).
+
+### What shipped in Unit 1 (2026-10-21) — do not re-hunt
+- **Geometry only — NO render-path change.** The tier switch swaps the element's LIVE geometry; the
+  preview and the compositor read `X/Y/W/H` + `ClipShape` exactly as before.
+- `Models/VerticalCameraLayout.cs` (new): the pure math — band x 656.25, w 607.5, h 1080; two
+  607×540 areas; six spots; default tile **270×152 master px** (= 480×270 in the 1080×1920 output),
+  **bottom-right** spot; inset 32 master px.
+- `Models/WebcamSceneConfig.cs`: the vertical placement is persisted in **seven additive columns**
+  (`VerticalX/Y/Width/Height/VerticalClipShape/VerticalRectWidth/VerticalRectHeight`, NULL = "this
+  scene has no vertical placement yet"); the 16:9 layout stays in the old columns and is **parked** in
+  the transient `Landscape*` fields while the vertical tier is live. `BeginVerticalLayout` /
+  `EndVerticalLayout` / `CommitLiveLayoutToVertical` do the swap.
+- `Models/SceneElement.cs`: `X/Y/Width/Height` are now **`virtual`** so the webcam clamps EVERY write
+  (drag, resize, typed fields) into the band — outside the band = invisible in vv.
+- `ViewModels/MainViewModel.Webcam.cs`: `IsVerticalTier`/`VerticalBand` + `ResolveVerticalCameraLayouts`
+  (the tier swap; the **Live scene gets its tile automatically** on the first vertical switch) +
+  `MoveWebcamInVerticalTier`/`SnapWebcamInVerticalTier` (the six-spot snap, by the tile's CENTRE).
+  `MainViewModel.Streaming.cs` `ApplyStreamQuality` is the tier-change hook.
+- `Controls/LeftPanel.xaml`: the webcam properties gained a **Geometry** section (X/Y/W/H) bound to
+  the live placement, gated on the VM's `IsWebcamSelected` (NOT `SelectedElement.IsWebcam` — the TASK 51
+  test finds that panel by binding text and would match twice).
+- `Controls/PreviewPane.xaml.cs`: dragging/resizing a webcam under the vertical tier routes through the
+  VM's snap instead of free-floating over the master.
+- Test seam: the drag lives in a **VM method**, so the test drives it without synthesising mouse input.
+
+### What shipped in Unit 2 (the Chat scene, 2026-10-21) — do not re-hunt
+- **Rect only, and the lock is on the MODEL, not the UI.** `WebcamSceneConfig.VerticalShapeLocked`
+  (set per scene by the VM) **overrides the `ClipShape` property** → a locked camera cannot become
+  Round by any writer (the toggle, the Shape button, the placement swap). `SceneElement.ClipShape`
+  and `SceneElement.ToggleClipShape()` are `virtual` for this. The lock is cleared **before** the
+  16:9 layout comes back, so the desktop shape is restored.
+- **The circle is not OFFERED:** `MainViewModel.CanToggleClipShape` is false for a Chat camera in the
+  vertical tier → the Shape button in the webcam's properties **disappears** (not just disabled).
+  `MainViewModel.cs` raises it on the selection change; `MainViewModel.Streaming.cs` on the tier change.
+- **Two sizes, snapped by the nearer one:** `VerticalCameraLayout.SizeFor(band, requestedWidth)` →
+  the small tile (270×152) or one whole area (607.5×540). The resize handle therefore has two
+  detents instead of any size in between.
+- **An enlarged camera fills the area its centre is in** — top or bottom (`VerticalCameraLayout.AreaFor`).
+- **The Chat camera is auto-tiled** like the Live one when the vertical tier is picked (otherwise the
+  vertical chat stream has no camera at all). `ResolveVerticalCameraLayout` now auto-tiles Live **and**
+  Chat; Starting/BRB/Ending keep their 16:9 placement.
+- The preview's resize routes through `MainViewModel.ResizeWebcamInVerticalTier` (the Chat camera's
+  discrete size + the snap); the drag routes through `MoveWebcamInVerticalTier` (assign → clamp →
+  snap, so the enlarged camera can be dragged from the top area to the bottom one).
+- *Test:* `ytLive.Tests/VerticalChatCameraLayoutTests.cs` — **PASSES** (in Chat under the vertical
+  tier, enlarging fills the full top area and the circle option is not offered).
+
+### Units (each: ONE Good Dog integration test, own commit, memory in the same commit)
+1. ✅ **vv camera layout (Unit 1)** — shipped 2026-10-21. Stored separately per scene, resolved when the
+   tier changes. Live: small tile (circle or rect) snapped to one of six spots; drag like the socials +
+   properties entry.
+   *Test:* `ytLive.Tests/VerticalWebcamLayoutTests.cs` — with the vertical tier active, dragging the Live
+   camera to top-right places it top-right inside the band; switching back to 16:9 restores the original
+   layout exactly; both placements survive a save + reload. **PASSES.**
+2. ✅ **vv · Chat (Unit 2)** — shipped 2026-10-21. Rect enforced with the circle option unavailable, plus
+   enlarge-to-one-area (607×540) filling the top or the bottom area by where the camera is.
+   *Test:* `ytLive.Tests/VerticalChatCameraLayoutTests.cs` — in Chat under the vertical tier, enlarge sets
+   the full top area and the circle option is not offered. **PASSES.**
+
+## Next step
+- **✅ TASK 63 + popup-click fix verified by creator (2026-10-22)** — clicking a colour in the
+  Border Color `YtComboBox` dropdown now stays inside `LeftPanel` (`IsDescendantOf` crosses
+  `PopupRoot` → `PART_Popup` via `LogicalTreeHelper.GetParent`), updates the webcam border colour,
+  and does not exit the properties listing.
+- **Creator check (needs the creator's hands)** — the last piece of the vv feature: switch the
+  resolution dropdown to "Vertical 1080p60", confirm the Live camera tile lands inside the band and
+  the **Circle** option (TASK 59 turned the Shape button into a Rect | Circle choice) turns the tile
+  into a circle there, open the **Chat** scene and confirm the **Circle** option is **gone** (rect only)
+  and that dragging the tile up and enlarging it fills a whole 607×540 area, then
+  switch back and confirm the desktop layout is untouched. The unit tests cover the geometry, not the
+  eyeball.
+- **⏸ Distribution & packaging is DEFERRED (creator ruling 2026-10-26) — do not pick it up until
+  we are close to v1.** The creator's reasons: the remaining programming tasks are far from
+  release, and a **complete UX redesign is about to start** — so packaging/signing/updater/route
+  decisions would chase scope that is about to move. Nothing distribution-related is urgent now.
+  Frozen: TASK 48 items 6-8, the signing decision, the updater choice, and the **route contradiction**
+  (`ai.md` says Store route DEAD → direct + Steam; `TASKS.md`/`TASKS/task-48-…`/this file still say
+  Store MSIX + Store IAP). That contradiction is to be settled in ONE distribution sweep at the
+  revisit, not patched piecemeal in the meantime. Detail: `TASKS.md` → Open items → the ⏸ TASK 48
+  bullet.
+- Nothing else is queued for llamacasty — the creator queues work.
+
+## Open (operational)
+- **Follow-up (not fixed — out of scope for TASK 61):** the **web source** block's geometry rows in
+  `Controls/LeftPanel.xaml` (the `SelectedElement.IsWebSource` panel, ~lines 387-402) have the
+  identical shape and the identical defect as the webcam's did — the Y/H fields stretch to fill the
+  row. Same one-line-per-field fix as TASK 61, when the creator wants it.
+- **✅ FIXED in TASK 63:** the border-colour swatches now carry a 1px `BorderBrush="#2a3a5e"`, so
+  the black (`#000000`) and dark swatches are visible against the dark menu (`#16213e`).
+- **Follow-up spotted while doing TASK 63 (not fixed — out of scope for that change):** the theme has
+  **no implicit `Button` style**, so every plain `<Button>` in the app still renders with the light
+  WPF system template (`Controls/LeftPanel.xaml` ×7, `Controls/CameraPickerDialog.xaml` ×2). The
+  border picker's `...` button was one of them and is gone; the rest are still there. A theme-level
+  implicit `Button` style would fix them all at once — that is a creator-queued task, not a silent edit.
+- **GOG Galaxy launcher shows "offline" (2026-10-21) — GOG's own overnight outage, NOT Windows.** GOG
+  put `www.gog.com` behind a maintenance page (503) and their Fastly services for `auth.gog.com` /
+  `api.gog.com` / `remote-config.gog.com` return `500 "Fastly error: unknown domain"`; the page itself
+  says *"Galaxy Launcher will also be down."* **Window: 00:00–08:11 local on 2026-10-21** — the Wayback
+  snapshot of `www.gog.com/en/` at 06:56 UTC is HTTP 200 with the full live storefront. `status.gog.com`
+  is NXDOMAIN globally. Local exoneration chain: genuine `GOG sp. z o.o → DigiCert` cert (no MITM),
+  local DNS == Google's authoritative answers, real Fastly POP headers, and GOG's own non-Fastly servers
+  still answering. **Nothing to fix locally** — wait for GOG. Galaxy's logs (incl. the rotated ones) show
+  no API-status failures between Oct 10 and Oct 20. Diagnosis recipe + the `webfetch`-is-not-an-
+  independent-egress trap: `MyMistakes.md` → 2026-10-21 GOG Galaxy "offline". Galaxy 2.0 logs live in
+  `C:\ProgramData\GOG.com\Galaxy\logs\` (NOT `%LOCALAPPDATA%`). ⚠️ that folder also holds a **2.7 GB
+  `cef.log`** (since Jul 13) — disk hygiene, see TASK 55.
+- **verify.sh's known-failure whitelist is too loose** (confirmed twice 2026-10-16): require EVERY failure
+  line to be whitelisted, and add `MasterLimiter_CapsTheLiveMix_OnThePipe` +
+  `RealMouseDrag_OnTheLayerList_PersistsTheReorder` to the list.
+- **A pre-existing stash is still sitting there:** `stash@{0}` = "WIP on main: 0464593 Compositor:
+  fast-path opaque 1:1 when source fills canvas" (NOT this session's; do not drop blindly).
+- The judder reproduction take in the FAILING geometry (vertical 1080p60 first) is still outstanding — no
+  fix until a take names the stage.
+- ⛔ Sudo password rotation pending (user; then update both `CREDENTIALS.md` password lines).
+- ✅ **TASK 56 secret scan — DONE 2026-10-22, CLEAN.** 432 reachable commits (all branches, 35
+  tags, reflog, stash) + 63 dangling commits + the worktree: **0 real secrets**. 4 rule hits, all
+  false positives (`README.md:79` = the `your-client-secret` doc placeholder;
+  `TokenStoreTests.cs:22` = a 9-char test dummy). `CREDENTIALS.md`/`MARCOM.md`/
+  `Helpers/OAuthCredentials.cs` were never tracked. ⚠️ the repo was **already public** (anonymous
+  GET → 200, API `private = false`) when the scan ran — the gate came late, but nothing leaked.
+  Method + verdict: `TASKS/task-56-secret-scan.md`.
+- TASK 55 disk hygiene: slice 1 (log rotation) **shipped 2026-10-22** — see the At-a-glance bullet.
+  Slices 2 (temp alert-clip cleanup) + 3 (low-disk guard before recording) are open. (The GOG
+  Galaxy `cef.log` at 2.7 GB is NOT ours.)
+
+## Tests
+- Last full run: **438/438 passed, 0 warnings** (2026-10-22 — after TASK 48 slice 2's
+  manifest guard; the run before was 437/437 after slice 3's `StorePackagingTests`, then
+  436/436 after TASK 55 slice 1's `AppLogRotationTests` and 435/435 after TASK 63). The one
+  failure seen earlier in the
+  session was `LayerReorderPersistenceTests.RealMouseDrag_OnTheLayerList_PersistsTheReorder`,
+  which **passes in isolation** (re-run: 3/3) — the known real-mouse flake, not a regression.
+- Known flaky-by-environment (all pass in isolation): `AudioPipelineTests.Mix_HonorsProviderGains…`,
+  `MasterLimiter_CapsTheLiveMix_OnThePipe`, `LayerReorderPersistenceTests.RealMouseDrag…`,
+  `Round_Clip_Corner…`.
+  - ⚠️ **`LayerReorderPersistenceTests.RealMouseDrag_OnTheLayerList_PersistsTheReorder` is NOT
+    "passes in isolation" any more.** During this session it FAILED ALONE on a **clean tree** at
+    `58b9a7d` (the vv work stashed) with the same "Expected: ImgC / Actual: ImgA" — i.e. it is an
+    environment/real-mouse flake, **not** a regression from the vv work — and it PASSES in the
+    full-suite run (429/429). Treat it as environment-dependent, and don't chase it as a regression
+    without stashing first.
+
+## Secrets / paths (do not re-hunt)
+- Layout DB: `%APPDATA%\ytLlive\ytLlive.db` (SQLite, full-rewrite per save). Auth:
+  `%APPDATA%\ytLlive\ytLlive.auth` (DPAPI). Startup log: `%APPDATA%\ytLlive\startup.log`
+  (23MB — now CAPPED at 5 MB with one rolled copy, TASK 55).
+- Recordings land in `C:\Users\gramp\Downloads\recordings\` (`ty-<date>-<time>-<ms>-<seq>.mp4`; a
+  duplicate name gets a `-2` suffix).
+- **Conversation history:** `~/.local/share/opencode/opencode.db`, table **`session_message`** — creator
+  turns are `type='user'` with text in `data.text`; my turns are `type='assistant'` with reasoning AND the
+  rendered reply concatenated into `content[0].text`. The **reply marker's verbatim string is recorded in
+  `MyMistakes.md`**.
+- LAN credentials: `CREDENTIALS.md` (gitignored) — **⚠️ stale for HA: it says `192.168.50.144`, the real
+  Home Assistant is `192.168.50.145`** (`homeassistant.local`, HAOS 18.2, Core 2026.10.1, SSH
+  `gramps`/`einstein`, `/config` root-owned). `gordito` is `.144`. Fix this file when next editing it.
+- Google Cloud OAuth project number `198374416003`, owned by `llamachile.shop@gmail.com` — verify at
+  `https://console.cloud.google.com/apis/credentials?project=198374416003`.
+
+## Open (operational) — officerFriendly / PS5 "DNS errors" (2026-10-17, off-repo)
+- **Root cause: a ~43 h-wrong system clock on officerFriendly × `dnssec = true`.** Pi 400, **no RTC
+  hardware at all**, healthy oscillator (−7.39 ppm). Journal shows +54 min, +7 h, +42.9 h steps.
+  `pihole-FTL.db`: **1,688,396 `dnssec=3` rows on 10-11, 839,276 on 10-12 vs ≤23 other days**, hitting
+  PSN endpoints = the PS5's "DNS errors". KSK-rollover theory **retracted**.
+- **Pending creator decision (do not apply unilaterally):** tighten
+  `/etc/systemd/timesyncd.conf.d/lan.conf` to `PollIntervalMinSec=16` / `PollIntervalMaxSec=64` /
+  `ConnectionRetrySec=8` / `SaveIntervalSec=30`, and/or add a DS3231 RTC (`i2c-tools` already installed).
+- **LAN DNS routing vs creator intent:** DHCP still hands out `.26` + `.1` (clients query Pi-hole
+  directly) whereas the creator wants everything → `.1` with BBR forwarding. Also `dnssec = true` on
+  Pi-hole duplicates dnscrypt-proxy's `require_dnssec = true`. Both offered-for-veto, not done.
+- Router is the DHCP server (ASUS ROG GT-BE98 Pro `.1`) — **Pi-hole `.26` is DNS only**, its
+  `dhcp.leases` is 0 bytes.

Helpers/AppLog.cs

@@ -5,26 +5,40 @@ namespace ytLive.Helpers;
 /// <summary>
 /// Minimal file logger used to diagnose startup/shutdown crashes on Windows,
 /// where the WPF app has no visible console. Writes to
-/// %APPDATA%\ytLlive\startup.log, appending synchronously so entries survive
-/// a hard crash.
+/// %APPDATA%\ytLlive\startup.log (or a per-instance subfolder in DEBUG — see
+/// InstanceProfile), appending synchronously so entries survive a hard crash.
 /// </summary>
 public static class AppLog
 {
-    private static readonly string LogPath = Path.Combine(
-        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
-        "ytLlive",
-        "startup.log");
+    /// <summary>The cap for the live log file. Past this, it rolls to <c>startup.1.log</c>.</summary>
+    private const long DefaultMaxBytes = 5 * 1024 * 1024;
+
+    /// <summary>How many rolled copies to keep (startup.1.log, startup.2.log, …).</summary>
+    private const int RetainedFiles = 1;
+
+    private static readonly string DefaultLogPath = Path.Combine(
+        InstanceProfile.DataRoot, "startup.log");
 
     private static readonly object Gate = new();
 
+    /// <summary>Test seam: point the log somewhere else. Null = the real profile's log.</summary>
+    internal static string? PathOverride { get; set; }
+
+    /// <summary>Test seam: the cap that triggers a roll.</summary>
+    internal static long MaxBytes { get; set; } = DefaultMaxBytes;
+
+    private static string LogPath => PathOverride ?? DefaultLogPath;
+
     public static void Write(string message)
     {
         try
         {
             lock (Gate)
             {
-                Directory.CreateDirectory(Path.GetDirectoryName(LogPath)!);
-                File.AppendAllText(LogPath, $"{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff} {message}{Environment.NewLine}");
+                var path = LogPath;
+                Directory.CreateDirectory(Path.GetDirectoryName(path)!);
+                LogRotation.RollIfNeeded(path, MaxBytes, RetainedFiles);
+                File.AppendAllText(path, $"{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff} {message}{Environment.NewLine}");
             }
         }
         catch

Helpers/ClosedBoxTemplateSelector.cs

@@ -0,0 +1,33 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+
+namespace ytLive.Helpers;
+
+/// <summary>Gives a ComboBox's CLOSED box a different template from its drop-down
+/// rows (TASK 63).
+///
+/// <para>WPF asks an <see cref="ItemTemplateSelector"/> with the ContentPresenter's
+/// templated parent: the <see cref="ComboBox"/> itself when it renders the closed
+/// selection box, the <see cref="ComboBoxItem"/> when it renders a row. That is the
+/// only way to tell the two apart — <c>ComboBox.SelectionBoxItemTemplate</c> is
+/// read-only, and WPF copies <c>ItemTemplate</c> into it, so a ComboBox otherwise
+/// cannot show one thing when shut and another when open.</para>
+///
+/// <para>Verified against WPF on .NET 8 (2026-10-21): with the rows' presenter the
+/// templated parent is the ComboBoxItem, with the closed box's it is the ComboBox.</para>
+/// </summary>
+public sealed class ClosedBoxTemplateSelector : DataTemplateSelector
+{
+    /// <summary>The template for the closed box — what the creator reads while the
+    /// drop-down is shut.</summary>
+    public DataTemplate? ClosedTemplate { get; set; }
+
+    /// <summary>The template for the drop-down rows.</summary>
+    public DataTemplate? RowTemplate { get; set; }
+
+    public override DataTemplate? SelectTemplate(object item, DependencyObject container)
+        => container is FrameworkElement { TemplatedParent: ComboBox }
+            ? ClosedTemplate
+            : RowTemplate;
+}

Helpers/DroppedFramesToBrushConverter.cs

@@ -0,0 +1,23 @@
+using System.Globalization;
+using System.Windows.Data;
+using System.Windows.Media;
+
+namespace ytLive.Helpers;
+
+public class DroppedFramesToBrushConverter : IValueConverter
+{
+    private static readonly SolidColorBrush Attention = new(Color.FromRgb(0xff, 0x8c, 0x3a));
+    private static readonly SolidColorBrush Clean = new(Colors.White);
+
+    static DroppedFramesToBrushConverter()
+    {
+        Attention.Freeze();
+        Clean.Freeze();
+    }
+
+    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        => value is int dropped && dropped > 0 ? Attention : Clean;
+
+    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        => throw new NotSupportedException();
+}

Helpers/DroppedPercentConverter.cs

@@ -0,0 +1,20 @@
+using System.Globalization;
+using System.Windows.Data;
+
+namespace ytLive.Helpers;
+
+public class DroppedPercentConverter : IMultiValueConverter
+{
+    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+    {
+        var dropped = values.Length > 0 && values[0] is int d ? d : 0;
+        var fps = values.Length > 1 && values[1] is double f ? f : 0;
+        var duration = values.Length > 2 && values[2] is TimeSpan t ? t : TimeSpan.Zero;
+        var total = fps * duration.TotalSeconds;
+        var percent = total > 0 ? dropped / total * 100 : 0;
+        return $"{dropped} ({percent.ToString("0.0", CultureInfo.InvariantCulture)}%)";
+    }
+
+    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+        => throw new NotSupportedException();
+}

Helpers/FrameCadence.cs

@@ -0,0 +1,123 @@
+using System;
+using System.Diagnostics;
+
+namespace ytLive.Helpers;
+
+/// <summary>
+/// Arrival cadence for one window of a timestamped frame stream: how many frames
+/// arrived, how far apart they were, and how many gaps were long enough to read
+/// as a hitch. Fed any shared monotonic clock (<see cref="Stopwatch.GetTimestamp"/>
+/// values, or a device's system-relative stamps on the same clock) and read through
+/// <see cref="Summarize"/>.
+///
+/// Why it exists: a 60fps container makes a missing camera frame indistinguishable
+/// from a padded repeat. rawvideo carries no per-frame timestamps — ffmpeg stamps
+/// frames by ARRIVAL at the declared rate — so the OBS "duplicate on lag" loop
+/// (FramePump) emits 300 authored frames per 5s whether the renderer managed 300
+/// composites or 84. The recorded file therefore cannot name the stage that lost
+/// the frames; only these counters can. The same counter run twice tells the two
+/// apart: the camera's OWN timestamps vs our ARRIVAL timestamps. Steady camera
+/// stamps with ragged arrivals means WE dropped it (compositor/reader); ragged in
+/// both means the camera, USB link, or driver did.
+/// </summary>
+public sealed class FrameCadence
+{
+    /// <summary>Default hitch threshold in ms. 50ms is ~1.5x a 30fps period — a
+    /// missed 30fps frame arrives as ~66ms — so this counts dropped frames without
+    /// flagging ordinary jitter (a 33ms frame can legitimately measure 35ms).</summary>
+    public const double DefaultHitchThresholdMs = 50;
+
+    private readonly double _hitchThresholdMs;
+    private long _firstTicks;
+    private long _previousTicks;
+    private double _gapTicksTotal;
+    private int _frames;
+    private int _gaps;
+    private int _hitches;
+    private double _longestGapMs;
+
+    public FrameCadence(double hitchThresholdMs = DefaultHitchThresholdMs)
+    {
+        if (hitchThresholdMs <= 0)
+            throw new ArgumentOutOfRangeException(nameof(hitchThresholdMs), hitchThresholdMs,
+                "Hitch threshold must be positive.");
+        _hitchThresholdMs = hitchThresholdMs;
+    }
+
+    public int Frames => _frames;
+    public int Gaps => _gaps;
+    public int Hitches => _hitches;
+    public double HitchThresholdMs => _hitchThresholdMs;
+
+    /// <summary>Records one frame at <paramref name="timestampTicks"/> on the shared
+    /// monotonic clock. Monotonicity is asserted, not trusted: an out-of-order stamp
+    /// (a device whose clock domain differs from ours, a wrapped counter, a dropped
+    /// timestamp) is counted as a frame but produces no gap AND does not become the
+    /// reference for the next one — otherwise a single bad stamp would poison both
+    /// its own interval and the one after it, inventing a multi-second "hitch".</summary>
+    public void Add(long timestampTicks)
+    {
+        if (_frames == 0)
+        {
+            _firstTicks = timestampTicks;
+            _previousTicks = timestampTicks;
+            _frames++;
+            return;
+        }
+
+        var delta = timestampTicks - _previousTicks;
+        _frames++;
+        if (delta <= 0) return;
+        var gapMs = delta * 1000d / Stopwatch.Frequency;
+        _gaps++;
+        _gapTicksTotal += gapMs;
+        if (gapMs > _longestGapMs) _longestGapMs = gapMs;
+        if (gapMs >= _hitchThresholdMs) _hitches++;
+        _previousTicks = timestampTicks;
+    }
+
+    public FrameCadenceSummary Summarize()
+    {
+        var spanMs = _frames >= 2
+            ? (_previousTicks - _firstTicks) * 1000d / Stopwatch.Frequency
+            : 0d;
+        // Rate is gaps-per-span, not frames-per-span: N frames span N-1 periods, and
+        // counting the extra interval would report one extra frame per window.
+        var rate = _gaps > 0 && spanMs > 0 ? _gaps / (spanMs / 1000d) : 0d;
+        return new FrameCadenceSummary(
+            _frames, rate, spanMs, _gaps, _hitches, _longestGapMs,
+            _gaps > 0 ? _gapTicksTotal / _gaps : 0d, _hitchThresholdMs);
+    }
+
+    /// <summary>Starts a fresh window, keeping the configured threshold.</summary>
+    public void Reset()
+    {
+        _firstTicks = 0;
+        _previousTicks = 0;
+        _gapTicksTotal = 0;
+        _frames = 0;
+        _gaps = 0;
+        _hitches = 0;
+        _longestGapMs = 0;
+    }
+}
+
+/// <summary>One measured cadence window — see <see cref="FrameCadence"/>.</summary>
+public readonly record struct FrameCadenceSummary(
+    int Frames,
+    double RatePerSecond,
+    double SpanMs,
+    int Gaps,
+    int Hitches,
+    double LongestGapMs,
+    double AverageGapMs,
+    double HitchThresholdMs)
+{
+    /// <summary>One-line log form. Identical in shape from every producer (camera
+    /// source, frame pump) so two lines can be read against each other: same window
+    /// length, same fields, same order.</summary>
+    public string Describe(string label) => Frames == 0
+        ? $"{label} no frames"
+        : $"{label} {Frames}f/{SpanMs / 1000d:F1}s {RatePerSecond:F1}/s, {Gaps} gaps, " +
+          $"{Hitches} >= {HitchThresholdMs:F0}ms, avg {AverageGapMs:F1}ms, longest {LongestGapMs:F1}ms";
+}

Helpers/HexToBrushConverter.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Globalization;
+using System.Windows.Data;
+using System.Windows.Media;
+
+namespace ytLive.Helpers;
+
+/// <summary>Turns a "#RRGGBB" hex string into a brush, so a template can paint a colour
+/// swatch straight from the palette (TASK 63).
+///
+/// <para>Without it the UI would have to hand-build a brush in code — the hand-painted
+/// approach the theme forbids. A colour is data; the theme paints it.</para></summary>
+public class HexToBrushConverter : IValueConverter
+{
+    public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        if (value is not string hex || string.IsNullOrWhiteSpace(hex))
+            return Brushes.Transparent;
+        try
+        {
+            var colour = (Color)ColorConverter.ConvertFromString(hex.Trim());
+            return new SolidColorBrush(colour);
+        }
+        catch (FormatException)
+        {
+            return Brushes.Transparent;
+        }
+    }
+
+    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+        => throw new NotSupportedException("A brush is not a hex value.");
+}

Helpers/InstanceProfile.cs

@@ -0,0 +1,77 @@
+using System;
+using System.IO;
+
+namespace ytLive.Helpers;
+
+/// <summary>
+/// Which run of LlamaCasty this process is, and where its private state lives.
+/// <para><b>Dev-only affordance (creator directive, 2026-09-26).</b> Pre-1.0 the creator
+/// needs two instances side by side: one streaming, one screen-capturing the other.
+/// Two instances on one Windows profile collide on state, and two of those collisions
+/// are hard failures rather than annoyances:
+/// <list type="bullet">
+/// <item><b>The SQLite layout DB.</b> The app's model is read-whole-scene / write-whole-scene,
+/// so two instances saving different layouts clobber each other.</item>
+/// <item><b>The WebView2 user data folder.</b> Chromium takes an exclusive lock on it; the
+/// second instance of the same exe simply fails to start.</item>
+/// <item><b>The auth token store.</b> A test instance would overwrite the real YouTube
+/// sign-in.</item>
+/// <item><b>startup.log.</b> Two appenders interleave into one file, so a crash in either
+/// instance is ambiguous.</item>
+/// </list>
+/// So in <c>DEBUG</c> a process can claim an identity and gets its own private root
+/// under <c>instances\&lt;id&gt;</c>: <c>$env:YTLIVE_INSTANCE=2; dotnet run</c>.
+/// Recording, screen capture and the ffmpeg <c>tools\</c> cache are deliberately LEFT
+/// shared — the cache should be shared, and the creator chooses the record folder.
+/// Global hotkeys are also left alone: if both instances register the same one, Windows
+/// refuses the second, which is the correct answer.</para>
+/// <para><b>At 1.0 this disappears.</b> The whole implementation is inside
+/// <c>#if DEBUG</c>; a Release build compiles to the two pass-throughs at the bottom —
+/// no environment variable, no alternate folder, not even the variable's NAME in the
+/// binary. Call sites are unconditional, so Release cannot accidentally diverge: it
+/// always resolves the one real user profile.</para>
+/// </summary>
+public static class InstanceProfile
+{
+#if DEBUG
+    /// <summary>Environment variable naming this instance. Absent or blank = the primary
+    /// instance on the real user profile.</summary>
+    public const string InstanceVariable = "YTLIVE_INSTANCE";
+
+    /// <summary>This instance's id, or null for the primary instance.</summary>
+    public static string? Id => Sanitize(Environment.GetEnvironmentVariable(InstanceVariable));
+
+    /// <summary>Private state root: the real profile normally, a per-instance subfolder
+    /// when an id is claimed.</summary>
+    public static string DataRoot => Id is { } id
+        ? Path.Combine(DefaultRoot, "instances", id)
+        : DefaultRoot;
+
+    /// <summary>Chromium's user data folder, or null to let WebView2 pick its default
+    /// (which is what Release always does). Must be per-instance or the second
+    /// instance dies on Chromium's exclusive lock.</summary>
+    public static string? WebViewDataFolder => Id is null ? null : Path.Combine(DataRoot, "webview2");
+
+    /// <summary>Reject anything that is not a plain path segment, so the variable can
+    /// never be used to walk out of the profile directory or name a UNC path.</summary>
+    private static string? Sanitize(string? raw)
+    {
+        if (string.IsNullOrWhiteSpace(raw)) return null;
+        var trimmed = raw.Trim();
+        foreach (var c in trimmed)
+            if (!char.IsLetterOrDigit(c) && c != '-' && c != '_') return null;
+        return trimmed;
+    }
+#else
+    // Release: one profile, no alternate paths, no environment variable. Multi-instance
+    // is a development affordance, not a shipping feature.
+    public static string DataRoot => DefaultRoot;
+    public static string? WebViewDataFolder => null;
+#endif
+
+    /// <summary>The one real user profile: <c>%APPDATA%\ytLlive</c>. Note the historical
+    /// double-L — do not "fix" it, users already have their layouts there.</summary>
+    public static string DefaultRoot => Path.Combine(
+        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
+        "ytLlive");
+}

Helpers/LogRotation.cs

@@ -0,0 +1,63 @@
+using System.IO;
+
+namespace ytLive.Helpers;
+
+/// <summary>
+/// Size-capped log rotation.
+/// <para>When a log file grows past a cap, it is rolled to <c>&lt;name&gt;.1.log</c> and a
+/// fresh one is started, keeping a bounded number of rolled files. The pattern is the
+/// one every sized logger uses — Serilog's file sink pairs <c>fileSizeLimitBytes</c>
+/// (the cap) with <c>retainedFileCountLimit</c> (how many rolled files to keep):
+/// https://github.com/serilog/serilog-sinks-file</para>
+/// <para><b>Why it lives here and not in the logger:</b> <see cref="AppLog"/>'s call surface
+/// (156 call sites) must not change, and the rotation rule is worth testing on its own —
+/// so the policy is a pure function over a path, and <see cref="AppLog"/> just calls it.</para>
+/// </summary>
+public static class LogRotation
+{
+    /// <summary>
+    /// Rolls <paramref name="logPath"/> if it has reached <paramref name="maxBytes"/>,
+    /// keeping <paramref name="retainedFiles"/> rolled copies
+    /// (<c>name.1.log</c>, <c>name.2.log</c>, …). Does nothing when the file is missing
+    /// or still under the cap.
+    /// <para>Never throws: a failed rotation must not take the app down — the log just
+    /// keeps growing, which is the old behaviour.</para>
+    /// </summary>
+    public static void RollIfNeeded(string logPath, long maxBytes, int retainedFiles)
+    {
+        try
+        {
+            var info = new FileInfo(logPath);
+            if (!info.Exists || info.Length < maxBytes)
+            {
+                return;
+            }
+
+            // Oldest first: name.1 → name.2 → … → name.N, then the live file → name.1.
+            for (var i = retainedFiles; i >= 1; i--)
+            {
+                var source = i == 1 ? logPath : RolledPath(logPath, i - 1);
+                var target = RolledPath(logPath, i);
+                if (!File.Exists(source))
+                {
+                    continue;
+                }
+
+                File.Move(source, target, overwrite: true);
+            }
+        }
+        catch
+        {
+            // Never let logging itself crash the app.
+        }
+    }
+
+    /// <summary>The rolled path for a given index: <c>startup.log</c> → <c>startup.1.log</c>.</summary>
+    public static string RolledPath(string logPath, int index)
+    {
+        var directory = Path.GetDirectoryName(logPath) ?? string.Empty;
+        var name = Path.GetFileNameWithoutExtension(logPath);
+        var extension = Path.GetExtension(logPath);
+        return Path.Combine(directory, $"{name}.{index}{extension}");
+    }
+}

Helpers/RelayCommandGeneric.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Windows.Input;
+
+namespace ytLive.Helpers;
+
+public class RelayCommand<T> : ICommand
+{
+    private readonly Action<T?> _execute;
+    private readonly Predicate<T?>? _canExecute;
+
+    public RelayCommand(Action<T?> execute, Predicate<T?>? canExecute = null)
+    {
+        _execute = execute;
+        _canExecute = canExecute;
+    }
+
+    public event EventHandler? CanExecuteChanged
+    {
+        add => CommandManager.RequerySuggested += value;
+        remove => CommandManager.RequerySuggested -= value;
+    }
+
+    public bool CanExecute(object? parameter)
+    {
+        if (parameter is T t) return _canExecute?.Invoke(t) ?? true;
+        return _canExecute?.Invoke(default) ?? true;
+    }
+
+    public void Execute(object? parameter)
+    {
+        if (parameter is T t) _execute(t);
+        else _execute(default);
+    }
+}

Helpers/StripPool.cs

@@ -0,0 +1,204 @@
+using System;
+using System.Threading;
+
+namespace ytLive.Helpers;
+
+/// <summary>
+/// A fixed pool of four DEDICATED background threads at <see cref="ThreadPriority.BelowNormal"/>
+/// that split one composite into horizontal row strips. The compositor needs the split to get
+/// render inside a 16.67ms slot, but it must not compete with the encoder, the WGC capture
+/// callbacks, the WebView2 chat or the game the user is playing — hence the hard cap of four
+/// and the demotion.
+///
+/// Research (2026-10-05, Unit 5): the demotion must NOT be done by poking
+/// <c>Thread.CurrentThread.Priority</c> inside <c>Parallel.For</c> — the pool is shared, so the
+/// demotion leaks into every unrelated work item that thread later runs
+/// (https://stackoverflow.com/questions/524483/net-backgroundworker-objects-thread-priority:
+/// "you have next to no control of which thread pool thread will actually run your task");
+/// https://stackoverflow.com/questions/1578599/c-sharp-lower-thread-priority-in-thread-pool:
+/// "You shouldn't mess with the priority of the regular ThreadPool, since you aren't the only
+/// consumer ... write your own producer/consumer queue, using your own Thread(s) as the
+/// consumer(s) — setting the thread priority yourself"). A real failed attempt confirmed it: a
+/// full test run after demoting the pool threads broke an unrelated audio-mix timing test.
+/// This class IS that producer/consumer queue; the caller thread is the producer and also runs
+/// one strip itself, so four workers never means five-way oversubscription.
+///
+/// Contract: <see cref="For"/> blocks until every strip has run, each strip must write only its
+/// own rows (the compositor's blits already partition by row), and it must not be called from
+/// inside a strip (the blits never nest).
+/// </summary>
+internal static class StripPool
+{
+    /// <summary>Four workers: the measured sweet spot on this box. Fewer leaves render over
+    /// budget; more steals cycles from the game and the encoder and made render worse, not better.</summary>
+    public const int Workers = 4;
+
+    /// <summary>Below this many rows the fan-out costs more than it saves — run it inline.</summary>
+    private const int MinRowsForFanOut = 64;
+
+    private static readonly object[] _queueLocks = CreateLocks();
+    private static readonly Queue<Strip>[] _queues = CreateQueues();
+    private static readonly Queue<Strip>[] _free = CreateQueues();
+    private static readonly SemaphoreSlim[] _signals = CreateSignals();
+    private static Thread[]? _threads;
+    private static int _roundRobin = -1;
+
+    private sealed class Strip
+    {
+        public int From;
+        public int To;              // exclusive
+        public Action<int>? Body;
+        public Batch? Owner;
+    }
+
+    private sealed class Batch
+    {
+        public int Remaining;
+        public Exception? Error;
+    }
+
+    /// <summary>Run <paramref name="body"/> for every row in [from, to), split across the pool.</summary>
+    public static void For(int from, int to, Action<int> body)
+    {
+        if (from >= to) return;
+
+        var rows = to - from;
+        if (rows < MinRowsForFanOut || !EnsureStarted())
+        {
+            for (var y = from; y < to; y++) body(y);
+            return;
+        }
+
+        // Strips are handed to whole workers (not per-row tasks) so the strip boundaries —
+        // and therefore the destination row each strip owns — are fixed before any of them run.
+        var strips = Math.Min(Workers, rows);
+        var chunk = (rows + strips - 1) / strips;
+        var batch = new Batch { Remaining = strips - 1 }; // the caller runs the last one
+
+        var first = from;
+        for (var k = 0; k < strips - 1; k++)
+        {
+            var end = Math.Min(first + chunk, to);
+            var w = NextWorker();
+            var strip = Rent(w);
+            strip.From = first;
+            strip.To = end;
+            strip.Body = body;
+            strip.Owner = batch;
+            lock (_queueLocks[w]) _queues[w].Enqueue(strip);
+            _signals[w].Release();
+            first = end;
+        }
+
+        try
+        {
+            for (var y = first; y < to; y++) body(y);
+        }
+        catch (Exception ex)
+        {
+            batch.Error ??= ex;
+        }
+
+        if (batch.Remaining > 0)
+        {
+            lock (batch)
+            {
+                while (batch.Remaining > 0) Monitor.Wait(batch);
+            }
+        }
+
+        if (batch.Error != null) throw new InvalidOperationException("A compositor strip failed.", batch.Error);
+    }
+
+    private static void Worker(int index)
+    {
+        var signal = _signals[index];
+        while (true)
+        {
+            signal.Wait();
+            Strip? strip = null;
+            lock (_queueLocks[index])
+            {
+                if (_queues[index].Count > 0) strip = _queues[index].Dequeue();
+            }
+            if (strip == null) continue; // released for an already-drained queue
+            var batch = strip.Owner!;
+            try
+            {
+                for (var y = strip.From; y < strip.To; y++) strip.Body!(y);
+            }
+            catch (Exception ex)
+            {
+                batch.Error ??= ex;
+            }
+            finally
+            {
+                strip.Body = null;
+                strip.Owner = null;
+                lock (_queueLocks[index]) _free[index].Enqueue(strip);
+                lock (batch)
+                {
+                    if (--batch.Remaining == 0) Monitor.PulseAll(batch);
+                }
+            }
+        }
+    }
+
+    private static Strip Rent(int worker)
+    {
+        lock (_queueLocks[worker])
+            return _free[worker].Count > 0 ? _free[worker].Dequeue() : new Strip();
+    }
+
+    private static int NextWorker()
+    {
+        var w = Interlocked.Increment(ref _roundRobin) % Workers;
+        return w < 0 ? w + Workers : w;
+    }
+
+    /// <summary>Start the workers on first use, so a WPF cold start pays nothing for them.</summary>
+    private static bool EnsureStarted()
+    {
+        if (_threads != null) return true;
+        lock (_signals)
+        {
+            if (_threads != null) return true;
+            var threads = new Thread[Workers];
+            for (var i = 0; i < Workers; i++)
+            {
+                var index = i; // capture per-iteration: the loop variable would be Workers by the time the thread runs
+                var t = new Thread(() => Worker(index), 256 * 1024)
+                {
+                    IsBackground = true,
+                    Name = $"compositor-strip-{i}",
+                    Priority = ThreadPriority.BelowNormal,
+                };
+                threads[i] = t;
+                t.Start();
+            }
+            _threads = threads;
+            return true;
+        }
+    }
+
+    private static object[] CreateLocks()
+    {
+        var l = new object[Workers];
+        for (var i = 0; i < Workers; i++) l[i] = new object();
+        return l;
+    }
+
+    private static Queue<Strip>[] CreateQueues()
+    {
+        var q = new Queue<Strip>[Workers];
+        for (var i = 0; i < Workers; i++) q[i] = new Queue<Strip>();
+        return q;
+    }
+
+    private static SemaphoreSlim[] CreateSignals()
+    {
+        var s = new SemaphoreSlim[Workers];
+        for (var i = 0; i < Workers; i++) s[i] = new SemaphoreSlim(0, int.MaxValue);
+        return s;
+    }
+}

Helpers/TokenStore.cs

@@ -14,9 +14,7 @@ namespace ytLive.Helpers;
 public static class TokenStore
 {
     public static string DefaultPath => Path.Combine(
-        Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
-        "ytLlive",
-        "ytLlive.auth");
+        InstanceProfile.DataRoot, "ytLlive.auth");
 
     public static void Save(YouTubeChannel channel, string? path = null)
     {

Helpers/index.md

@@ -6,7 +6,8 @@ Cross-cutting utilities. See [`schema.md`](../schema.md) for the memory-map conv
 |------|---------|
 | `ViewModelBase.cs` | `INotifyPropertyChanged` + `SetProperty<T>()` — base for all ViewModels |
 | `RelayCommand.cs` | `ICommand` implementation for all button actions |
-| `AppLog.cs` | File logger to `%APPDATA%\ytLlive\startup.log`; startup checkpoints + unhandled-exception capture (the crash this map is named for) |
+| `AppLog.cs` | File logger to `%APPDATA%\ytLlive\startup.log`; startup checkpoints + unhandled-exception capture (the crash this map is named for). Size-capped: rolls to `startup.1.log` at 5 MB (TASK 55) |
+| `LogRotation.cs` | The size-capped-rotation policy as a pure function over a path: roll `startup.log` → `startup.1.log` when it passes the cap, keeping N rolled copies. Separate from `AppLog` so the logger's 156-call-site surface never changes and the rule is testable alone (TASK 55) |
 | `FocusPreservingListBox.cs` | `ListBox` subclass that keeps selection/focus coherent when the selected item is deleted; `IsSelectable` predicate skips hidden scenes; drag-reorder guard |
 | `OAuthCredentials.cs` | Baked-in Google OAuth client ID/secret (desktop app; loopback callback) |
 | `TokenStore.cs` | DPAPI-protected OAuth session persistence (`%APPDATA%\ytLlive\ytLlive.auth`, CurrentUser scope); `Save`/`Load`/`Clear` — sign-in survives restarts |
@@ -14,6 +15,10 @@ Cross-cutting utilities. See [`schema.md`](../schema.md) for the memory-map conv
 | `InverseBoolToVisibilityConverter.cs` / `NotNullToVisibilityConverter.cs` | XAML value converters for visibility bindings |
 | `AllTrueToVisibilityConverter.cs` | Multi-value AND-gate → Visible; gates the layer-row capture menu items on row-IsBackground + staged-scene-is-Live (TASK 25) |
 | `CameraConflictProbe.cs` | Best-effort diagnostic: when a camera won't start, enumerates running processes known to hold cameras (OBS, Zoom, Teams, NVIDIA Broadcast, browsers, etc.) — Windows doesn't expose "which process has this device" via any public API, so this is a suspect list, not a verdict |
+| `StripPool.cs` | Four DEDICATED background threads at `BelowNormal` priority that split one composite into horizontal row strips (the caller runs a strip too); started lazily, runs inline below 64 rows. UNIT 5 — do NOT demote the ThreadPool from `Parallel.For`, it leaks into unrelated work (see [`docs/ai/frame-pipeline.md`](../docs/ai/frame-pipeline.md) → "Render budget") |
+| `FrameCadence.cs` | Pure arrival-cadence counter (`FrameCadence` + `FrameCadenceSummary.Describe`): frames, gaps, hitches, longest/avg gap for a window of a timestamped stream. Fed by `MediaCaptureFrameSource` (camera stamps vs our arrivals) and `FramePump` (distinct webcam Epochs that reached the output) — UNIT 0, see [`docs/ai/frame-pipeline.md`](../docs/ai/frame-pipeline.md) → "Frame cadence" |
+| `HexToBrushConverter.cs` | A "#RRGGBB" hex string → `SolidColorBrush` (transparent on bad input), so a template can paint a colour swatch straight from the palette. Registered in the theme as `HexToBrush` — the theme paints the colour, never the UI code (TASK 63) |
+| `ClosedBoxTemplateSelector.cs` | An `ItemTemplateSelector` that gives a ComboBox's CLOSED box a different template from its drop-down rows: WPF calls it with the `ContentPresenter`'s templated parent — the `ComboBox` for the closed box, the `ComboBoxItem` for a row. The only way to tell them apart (`SelectionBoxItemTemplate` is read-only and mirrors `ItemTemplate`) — TASK 63 |
 
 Related: [`Themes/Controls.xaml`](../Themes/Controls.xaml) styles the lists this
 class backs; [`Models/index.md`](../Models/index.md) and

KeepBroadcastDialog.xaml

@@ -0,0 +1,31 @@
+<Window x:Class="ytLive.KeepBroadcastDialog"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="Keep this broadcast?" Height="240" Width="460"
+        Icon="/ytLive;component/Assets/llamacasty-icon.png"
+        WindowStartupLocation="CenterOwner" ResizeMode="NoResize"
+        ShowInTaskbar="False" Background="#1a1a2e">
+
+    <Grid Margin="24">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
+        </Grid.RowDefinitions>
+
+        <TextBlock Grid.Row="0" Text="Keep this broadcast?" FontSize="18" FontWeight="Bold"
+                   Foreground="#e0e0e0" Margin="0,0,0,12"/>
+
+        <TextBlock Grid.Row="1" x:Name="MessageText" TextWrapping="Wrap" Foreground="#a0a0b0" FontSize="13"
+                   Margin="0,0,0,16"/>
+
+        <StackPanel Grid.Row="2" Orientation="Horizontal" HorizontalAlignment="Right">
+            <Button x:Name="DeleteBroadcastButton" Content="Delete" IsCancel="True" Click="Delete_Click"
+                    Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"
+                    ToolTip="Esc — delete the recording from YouTube"/>
+            <Button x:Name="KeepBroadcastButton" Content="Keep" IsDefault="True" Click="Keep_Click"
+                    Style="{StaticResource YtButton}" MinWidth="90"
+                    ToolTip="Enter — keep it on YouTube as a private video"/>
+        </StackPanel>
+    </Grid>
+</Window>

KeepBroadcastDialog.xaml.cs

@@ -0,0 +1,23 @@
+using System.Windows;
+
+namespace ytLive;
+
+/// <summary>Asked when a PRIVATE broadcast ends — the same contract as the recording's save
+/// dialog (creator ruling 2026-10-09): <b>Enter keeps</b> it on YouTube as a private video,
+/// <b>Escape deletes</b> it. <c>DialogResult == true</c> = keep; false (Delete, Escape, the X)
+/// = delete.</summary>
+public partial class KeepBroadcastDialog : Window
+{
+    public KeepBroadcastDialog(string title)
+    {
+        InitializeComponent();
+        MessageText.Text = string.IsNullOrWhiteSpace(title)
+            ? "Your private broadcast is on YouTube as a private video. Keep it, or delete it?"
+            : $"\u201c{title}\u201d is on YouTube as a private video. Keep it, or delete it?";
+        Loaded += (_, _) => KeepBroadcastButton.Focus();
+    }
+
+    private void Keep_Click(object sender, RoutedEventArgs e) => DialogResult = true;
+
+    private void Delete_Click(object sender, RoutedEventArgs e) => DialogResult = false;
+}

LICENSE

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
+
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so.  This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software.  The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable.  Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products.  If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary.  To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+  The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities.  However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work.  For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+  The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+  The Corresponding Source for a work in source code form is that
+same work.
+
+  2. Basic Permissions.
+
+  All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met.  This License explicitly affirms your unlimited
+permission to run the unmodified Program.  The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work.  This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright.  Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+  Conveying under any other circumstances is permitted solely under
+the conditions stated below.  Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+  No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+  4. Conveying Verbatim Copies.
+
+  You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+  You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+  5. Conveying Modified Source Versions.
+
+  You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+    a) The work must carry prominent notices stating that you modified
+    it, and giving a relevant date.
+
+    b) The work must carry prominent notices stating that it is
+    released under this License and any conditions added under section
+    7.  This requirement modifies the requirement in section 4 to
+    "keep intact all notices".
+
+    c) You must license the entire work, as a whole, under this
+    License to anyone who comes into possession of a copy.  This
+    License will therefore apply, along with any applicable section 7
+    additional terms, to the whole of the work, and all its parts,
+    regardless of how they are packaged.  This License gives no
+    permission to license the work in any other way, but it does not
+    invalidate such permission if you have separately received it.
+
+    d) If the work has interactive user interfaces, each must display
+    Appropriate Legal Notices; however, if the Program has interactive
+    interfaces that do not display Appropriate Legal Notices, your
+    work need not make them do so.
+
+  A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit.  Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+  6. Conveying Non-Source Forms.
+
+  You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+    a) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by the
+    Corresponding Source fixed on a durable physical medium
+    customarily used for software interchange.
+
+    b) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by a
+    written offer, valid for at least three years and valid for as
+    long as you offer spare parts or customer support for that product
+    model, to give anyone who possesses the object code either (1) a
+    copy of the Corresponding Source for all the software in the
+    product that is covered by this License, on a durable physical
+    medium customarily used for software interchange, for a price no
+    more than your reasonable cost of physically performing this
+    conveying of source, or (2) access to copy the
+    Corresponding Source from a network server at no charge.
+
+    c) Convey individual copies of the object code with a copy of the
+    written offer to provide the Corresponding Source.  This
+    alternative is allowed only occasionally and noncommercially, and
+    only if you received the object code with such an offer, in accord
+    with subsection 6b.
+
+    d) Convey the object code by offering access from a designated
+    place (gratis or for a charge), and offer equivalent access to the
+    Corresponding Source in the same way through the same place at no
+    further charge.  You need not require recipients to copy the
+    Corresponding Source along with the object code.  If the place to
+    copy the object code is a network server, the Corresponding Source
+    may be on a different server (operated by you or a third party)
+    that supports equivalent copying facilities, provided you maintain
+    clear directions next to the object code saying where to find the
+    Corresponding Source.  Regardless of what server hosts the
+    Corresponding Source, you remain obligated to ensure that it is
+    available for as long as needed to satisfy these requirements.
+
+    e) Convey the object code using peer-to-peer transmission, provided
+    you inform other peers where the object code and Corresponding
+    Source of the work are being offered to the general public at no
+    charge under subsection 6d.
+
+  A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+  A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling.  In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage.  For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product.  A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+  "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source.  The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+  If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information.  But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+  The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed.  Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+  Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it.  (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.)  You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+  Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+    a) Disclaiming warranty or limiting liability differently from the
+    terms of sections 15 and 16 of this License; or
+
+    b) Requiring preservation of specified reasonable legal notices or
+    author attributions in that material or in the Appropriate Legal
+    Notices displayed by works containing it; or
+
+    c) Prohibiting misrepresentation of the origin of that material, or
+    requiring that modified versions of such material be marked in
+    reasonable ways as different from the original version; or
+
+    d) Limiting the use for publicity purposes of names of licensors or
+    authors of the material; or
+
+    e) Declining to grant rights under trademark law for use of some
+    trade names, trademarks, or service marks; or
+
+    f) Requiring indemnification of licensors and authors of that
+    material by anyone who conveys the material (or modified versions of
+    it) with contractual assumptions of liability to the recipient, for
+    any liability that these contractual assumptions directly impose on
+    those licensors and authors.
+
+  All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10.  If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term.  If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+  If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+  Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+  8. Termination.
+
+  You may not propagate or modify a covered work except as expressly
+provided under this License.  Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+  However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+  Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+  Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
+not accept this License.  Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+  10. Automatic Licensing of Downstream Recipients.
+
+  Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License.  You are not responsible
+for enforcing compliance by third parties with this License.
+
+  An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations.  If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+  You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License.  For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+  11. Patents.
+
+  A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based.  The
+work thus licensed is called the contributor's "contributor version".
+
+  A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version.  For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+  Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+  In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement).  To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+  If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Use with the GNU Affero General Public License.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

MainWindow.xaml.cs

@@ -1,19 +1,10 @@
 using System;
-using System.Collections;
 using System.ComponentModel;
-using System.IO;
-using System.Net.Http;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
 using System.Windows.Media;
-using System.Windows.Media.Effects;
-using System.Windows.Threading;
-using System.Windows.Media.Animation;
-using System.Windows.Media.Imaging;
-using System.Windows.Shapes;
 using ytLive.Helpers;
-using ytLive.Models;
 using ytLive.ViewModels;
 
 namespace ytLive;
@@ -21,21 +12,29 @@ namespace ytLive;
 public partial class MainWindow : Window
 {
     private readonly MainViewModel _viewModel;
-    private readonly Dictionary<string, Storyboard> _activeBorderAnimations = new();
+    private Controls.TopBar _topBar = null!;
+    private Controls.PreviewPane _previewPane = null!;
+    private Controls.LeftPanel _leftPanel = null!;
 
     public MainWindow()
     {
         AppLog.Write("MainWindow ctor: before InitializeComponent");
         InitializeComponent();
+        SizeChanged += (_, e) => Helpers.AppLog.Write($"WIDTHS window={e.NewSize.Width:F0} "
+            + $"layers={LeftPanel.ActualWidth:F0} strip={SceneStrip.ActualWidth:F0} preview={PreviewPane.ActualWidth:F0}");
         AppLog.Write("MainWindow ctor: after InitializeComponent");
         _viewModel = (MainViewModel)DataContext;
-        _viewModel.InitWebView2(WebViewHostPanel);
         _viewModel.PropertyChanged += OnViewModelPropertyChanged;
-        _viewModel.ChatMessages.CollectionChanged += OnChatMessagesChanged;
+        // Don't steal focus from an exclusive-fullscreen game the creator is already
+        // playing (e.g. while starting a gameplay stream): activating our window would
+        // drop that game to the taskbar and make the desktop look "locked".
+        ShowActivated = !_viewModel.FullscreenGameRunningNow;
+        _topBar = (Controls.TopBar)FindName("TopBar")!;
+        _previewPane = (Controls.PreviewPane)FindName("PreviewPane")!;
+        _leftPanel = (Controls.LeftPanel)FindName("LeftPanel")!;
         UpdateTaskbarOverlay();
         UpdateSelectionOverlay();
-        AvatarImage.Source = null;
-        AvatarInitial.Visibility = Visibility.Collapsed;
+        _topBar.RefreshAvatar();
         RestoreWindowGeometry();
         AppLog.Write("MainWindow ctor: end");
     }
@@ -43,33 +42,62 @@ public partial class MainWindow : Window
     private void MainWindow_Loaded(object sender, RoutedEventArgs e)
     {
         AppLog.Write("MainWindow loaded");
+        // Web sources need the window HWND as the composition controller's parent,
+        // which does not exist in the ctor — InitWebView2 runs here (Loaded), after
+        // SourceInitialized. Nothing renders from web frames before this.
+        _viewModel.InitWebView2();
     }
 
-    // ─── Window geometry persistence (launch size/position) ───
-    // Saved on close (RestoreBounds so a maximized window remembers its
-    // un-maximize rect); restored in the ctor before the window is shown.
-    // Values clamp to the minimums and to the primary work area — a position
-    // saved on a since-disconnected secondary monitor falls back on-screen.
+    // ─── Window geometry (launch position/size) ───
+    // Launch POSITION is derived, never restored: upper-left of the work area plus
+    // padding (creator ruling 2026-10-04). The old restore clamped the saved position
+    // to [work.Left - width + 120, work.Right - 120] horizontally and
+    // [work.Top, work.Bottom - 80] vertically — ranges wide enough to leave the window
+    // almost entirely off-screen, which is what the creator was seeing ("below the
+    // fold"). Size and maximized state are still persisted. Placement math is pure and
+    // tested (WindowPlacementTests); changing it back to restore position is reverting
+    // this block only, since the saved values are still written.
+
+    /// <summary>Launch inset from the work-area corner, in device-independent units —
+    /// so it scales with DPI rather than being a fixed physical pixel count.</summary>
+    internal const double LaunchPadding = 75;
+
+    /// <summary>Upper-left of <paramref name="workArea"/> plus padding, clamped so the
+    /// window is never pushed off-screen. The clamp is the point: a window that fits
+    /// stays wholly visible, and one too big to fit falls back to the work-area origin
+    /// rather than hanging off an edge.</summary>
+    internal static Point TopLeftPlacement(Rect workArea, double width, double height, double padding)
+    {
+        var left = workArea.Left + padding;
+        var top = workArea.Top + padding;
+
+        if (width <= workArea.Width) left = Math.Min(left, workArea.Right - width);
+        else left = workArea.Left;
+
+        if (height <= workArea.Height) top = Math.Min(top, workArea.Bottom - height);
+        else top = workArea.Top;
+
+        return new Point(left, top);
+    }
 
     private void RestoreWindowGeometry()
     {
         try
         {
-            var saved = _viewModel.RestoreWindowState();
-            if (saved == null) return;
-            var (left, top, width, height, state) = saved.Value;
-
             var work = SystemParameters.WorkArea;
-            width = Math.Clamp(width, MinWidth, work.Width);
-            height = Math.Clamp(height, MinHeight, work.Height);
-            left = Math.Clamp(left, work.Left - width + 120, work.Right - 120);
-            top = Math.Clamp(top, work.Top, work.Bottom - 80);
+            var saved = _viewModel.RestoreWindowState();
 
-            Left = left;
-            Top = top;
+            // No saved state: keep the XAML-declared size rather than collapsing to Min*.
+            var width = Math.Clamp(saved?.Width ?? Width, MinWidth, work.Width);
+            var height = Math.Clamp(saved?.Height ?? Height, MinHeight, work.Height);
             Width = width;
             Height = height;
-            if (state == "Maximized") WindowState = WindowState.Maximized;
+
+            var place = TopLeftPlacement(work, width, height, LaunchPadding);
+            Left = place.X;
+            Top = place.Y;
+
+            if (saved?.State == "Maximized") WindowState = WindowState.Maximized;
         }
         catch (Exception ex)
         {
@@ -116,7 +144,7 @@ public partial class MainWindow : Window
             UpdateSelectionOverlay();
         else if (e.PropertyName == nameof(MainViewModel.AccountAvatarUrl)
               || e.PropertyName == nameof(MainViewModel.IsConnected))
-            LoadAvatarImage();
+            _topBar.RefreshAvatar();
     }
 
     private void MainWindow_Closing(object? sender, CancelEventArgs e)
@@ -141,782 +169,32 @@ public partial class MainWindow : Window
             : null;
     }
 
-    private static readonly HttpClient AvatarHttp = new() { Timeout = TimeSpan.FromSeconds(15) };
-    private string? _loadedAvatarUrl;
-
-    private async void LoadAvatarImage()
-    {
-        var url = _viewModel.AccountAvatarUrl;
-        if (!_viewModel.IsConnected)
-        {
-            ShowAvatarFallback(null);
-            return;
-        }
-        if (string.IsNullOrWhiteSpace(url))
-        {
-            AppLog.Write("Avatar: connected but no profile image URL on the session");
-            ShowAvatarFallback(null);
-            return;
-        }
-        if (url == _loadedAvatarUrl && AvatarImage.Source != null) return;
-        try
-        {
-            var bytes = await AvatarHttp.GetByteArrayAsync(url);
-            using var ms = new MemoryStream(bytes);
-            var bitmap = new BitmapImage();
-            bitmap.BeginInit();
-            bitmap.CacheOption = BitmapCacheOption.OnLoad;
-            bitmap.StreamSource = ms;
-            bitmap.EndInit();
-            bitmap.Freeze();
-            _loadedAvatarUrl = url;
-            AvatarImage.Source = bitmap;
-            AvatarInitial.Visibility = Visibility.Collapsed;
-        }
-        catch (Exception ex)
-        {
-            AppLog.Write($"Avatar load failed ({url}): {ex.Message}");
-            ShowAvatarFallback(_viewModel.AccountDisplayName);
-        }
-    }
-
-    private void ShowAvatarFallback(string? name)
-    {
-        _loadedAvatarUrl = null;
-        AvatarImage.Source = null;
-        AvatarInitial.Text = string.IsNullOrWhiteSpace(name) ? "?" : name.Substring(0, 1).ToUpperInvariant();
-        AvatarInitial.Visibility = Visibility.Visible;
-    }
-
-    private void SourceNameBox_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
-    {
-        if (sender is TextBox { IsVisible: true } box)
-        {
-            box.Focus();
-            box.SelectAll();
-        }
-    }
-
-    private void VolumeSlider_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is Slider slider)
-            SetSliderValueFromClick(slider, e);
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-            vm.SetVolumeAdjusting(true);
-    }
-
-    private void VolumeSlider_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-            vm.SetVolumeAdjusting(false);
-    }
-
-    private void VolumeSlider_LostMouseCapture(object sender, MouseEventArgs e)
-    {
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-            vm.SetVolumeAdjusting(false);
-    }
-
-    private void GameVolumeSlider_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is Slider slider)
-            SetSliderValueFromClick(slider, e);
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-            vm.SetGameVolumeAdjusting(true);
-    }
-
-    private void GameVolumeSlider_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-            vm.SetGameVolumeAdjusting(false);
-    }
-
-    private void GameVolumeSlider_LostMouseCapture(object sender, MouseEventArgs e)
-    {
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-            vm.SetGameVolumeAdjusting(false);
-    }
-
-    private static void SetSliderValueFromClick(Slider slider, MouseButtonEventArgs e)
-    {
-        if (FindParent<System.Windows.Controls.Primitives.Thumb>(e.OriginalSource as Visual) != null)
-            return;
-        var track = slider.Template.FindName("PART_Track", slider) as System.Windows.Controls.Primitives.Track;
-        if (track == null) return;
-        var pos = e.GetPosition(track);
-        var fraction = Math.Clamp(pos.X / track.RenderSize.Width, 0, 1);
-        slider.Value = slider.Minimum + fraction * (slider.Maximum - slider.Minimum);
-        e.Handled = true;
-    }
-
-    private static T? FindParent<T>(Visual? visual) where T : Visual
-    {
-        while (visual != null)
-        {
-            if (visual is T match) return match;
-            visual = VisualTreeHelper.GetParent(visual) as Visual;
-        }
-        return null;
-    }
-
-    private void MicSpeaker_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-        {
-            vm.ToggleMicMuteCommand.Execute(null);
-        }
-    }
-
-    private void GameSpeaker_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is FrameworkElement { DataContext: MainViewModel vm })
-        {
-            vm.ToggleGameMuteCommand.Execute(null);
-        }
-    }
-
-    // TRAX (TASK 9): left-click toggles play/pause (picks a track when none is
-    // loaded); right-click always opens the picker. The picker is the OS file
-    // dialog — the "never the OS viewer" rule covers the preview, not pickers.
-    private void TraxButton_Click(object sender, RoutedEventArgs e)
-    {
-        if (DataContext is ViewModels.MainViewModel vm)
-            vm.TraxLeftClick();
-    }
-
-    private void TraxButton_PreviewMouseRightButtonUp(object sender, MouseButtonEventArgs e)
-    {
-        if (DataContext is ViewModels.MainViewModel vm)
-            vm.TraxRightClick();
-        e.Handled = true; // the button's right-click context menu must not fire
-    }
-
-    private void GearButton_Click(object sender, RoutedEventArgs e)
-    {
-        if (sender is Button { ContextMenu: { } menu } button)
-        {
-            menu.PlacementTarget = button;
-            menu.Placement = System.Windows.Controls.Primitives.PlacementMode.Bottom;
-            menu.IsOpen = true;
-        }
-    }
-
-    private void BackToAbout_Click(object sender, RoutedEventArgs e)
-    {
-        if (DataContext is ViewModels.MainViewModel vm)
-        {
-            vm.IsLicensesOpen = false;
-            vm.IsLicenseEntryOpen = false;
-        }
-    }
-
-    private void AddSourceButton_Click(object sender, RoutedEventArgs e)
-    {
-        if (sender is Button { ContextMenu: { } menu } button)
-        {
-            menu.PlacementTarget = button;
-            menu.Placement = System.Windows.Controls.Primitives.PlacementMode.Bottom;
-            menu.IsOpen = true;
-        }
-    }
-
-    // ─── Preview image selection / move / resize ───
-    private void Thumbnail_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
-    {
-        if (sender is Border { DataContext: Scene scene })
-            _viewModel.TransitionToScene(scene);
-    }
-
-    private bool _isDraggingOverlay;
-    private bool _isResizing;
-    private Point _grabOffset;
-    private double _resizeAspect;
-
     private void Window_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
     {
         if (e.OriginalSource is not DependencyObject original) return;
         var form = _viewModel.BroadcastForm;
-        if (form.IsDrawerOpen && !IsDescendantOf(original, TextPullOutHost))
-            form.CloseDrawerCommand.Execute(null);
-        if (IsDescendantOf(original, PreviewGrid)) return;
-        if (IsDescendantOf(original, SourceList)) return;
-        if (IsDescendantOf(original, ElementsScrollViewer)) return;
+        var ypp = _viewModel.Ypp;
+        var test = _viewModel.TestSession;
+        if (!_previewPane.IsClickInsideDrawer(original))
+        {
+            if (form.IsDrawerOpen) form.CloseDrawerCommand.Execute(null);
+            if (ypp.IsDrawerOpen) ypp.CloseDrawerCommand.Execute(null);
+            if (test.IsDrawerOpen) test.CloseDrawerCommand.Execute(null);
+        }
+        if (_previewPane.IsClickInsidePreview(original)) return;
+        if (_leftPanel.IsClickInside(original)) return;
         _viewModel.SelectedElement = null;
     }
 
-    private static bool IsDescendantOf(DependencyObject? child, DependencyObject ancestor)
-    {
-        while (child != null && !ReferenceEquals(child, ancestor))
-        {
-            child = child is System.Windows.Media.Visual or System.Windows.Media.Media3D.Visual3D
-                ? VisualTreeHelper.GetParent(child)
-                : LogicalTreeHelper.GetParent(child);
-        }
-        return child != null;
-    }
-
     private void UpdateSelectionOverlay()
     {
         if (!_viewModel.IsEditMode)
         {
-            SelectionOverlay.Visibility = Visibility.Collapsed;
+            _previewPane.UpdateSelectionOverlay(false);
             return;
         }
-        var selected = _viewModel.SelectedElement is { } s && IsDraggableElement(s);
-        SelectionOverlay.Visibility = selected ? Visibility.Visible : Visibility.Collapsed;
-        if (selected)
-            OpacityValueText.Text = $"{Math.Round(_viewModel.SelectedElement!.Opacity * 100)}%";
-        TakeSnapshot();
-    }
-
-    private void OnChatMessagesChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
-    {
-        if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
-        {
-            ChatListBox.ScrollIntoView(ChatListBox.Items[^1]);
-        }
-    }
-
-    // Static images and the webcam share the move/resize/selection behavior.
-    private static bool IsDraggableElement(SceneElement element)
-        => element.IsDraggable;
-
-    private void MirrorButton_Click(object sender, RoutedEventArgs e)
-    {
-        if (_viewModel.SelectedElement is WebcamSceneConfig webcam)
-            webcam.IsMirrored = !webcam.IsMirrored;
-    }
-
-    private void ShapeButton_Click(object sender, RoutedEventArgs e)
-    {
-        if (_viewModel.SelectedElement is WebcamSceneConfig webcam)
-            webcam.ToggleClipShape();
-    }
-
-    private void WebcamMenu_ChangeWebcam(object sender, RoutedEventArgs e)
-        => _viewModel.ChangeWebcamCommand.Execute(null);
-
-    private void WebcamMenu_SetBorderAnimation(object sender, RoutedEventArgs e)
-    {
-        if (sender is not MenuItem { DataContext: SceneElement element, Tag: string tag }
-            || !Enum.TryParse<BorderAnimation>(tag, out var animation))
-            return;
-
-        element.BorderAnimation = animation;
-
-        StopBorderAnimation(element.Id);
-
-        if (animation == BorderAnimation.None) return;
-
-        var shape = FindBorderShape(sender as DependencyObject);
-        if (shape == null) return;
-
-        var sb = CreateBorderAnimation(animation, shape);
-        if (sb == null) return;
-
-        sb.Freeze();
-        _activeBorderAnimations[element.Id] = sb;
-        shape.BeginAnimation(Shape.OpacityProperty, null);
-        Storyboard.SetTarget(sb, shape);
-        sb.Begin();
-    }
-
-    private void StopBorderAnimation(string elementId)
-    {
-        if (_activeBorderAnimations.TryGetValue(elementId, out var old))
-        {
-            old.Stop();
-            _activeBorderAnimations.Remove(elementId);
-        }
-    }
-
-    private static Shape? FindBorderShape(DependencyObject? start)
-    {
-        var current = start;
-        while (current != null)
-        {
-            if (current is ContextMenu cm && cm.PlacementTarget is FrameworkElement target)
-            {
-                for (var i = 0; i < VisualTreeHelper.GetChildrenCount(target); i++)
-                {
-                    var child = VisualTreeHelper.GetChild(target, i);
-                    if (child is Shape s && (s is Rectangle or Ellipse) && !s.IsHitTestVisible)
-                        return s;
-                }
-                return null;
-            }
-            current = VisualTreeHelper.GetParent(current);
-        }
-        return null;
-    }
-
-    private static Storyboard? CreateBorderAnimation(BorderAnimation animation, Shape shape)
-    {
-        var sb = new Storyboard();
-        switch (animation)
-        {
-            case BorderAnimation.Pulse:
-                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.3, TimeSpan.FromSeconds(0.8), true);
-                break;
-            case BorderAnimation.Glow:
-                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.5, TimeSpan.FromSeconds(1.2), true);
-                break;
-            case BorderAnimation.Shimmer:
-                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.15, TimeSpan.FromSeconds(0.5), true);
-                break;
-            case BorderAnimation.Electricity:
-                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.2, TimeSpan.FromSeconds(0.1), true);
-                break;
-            case BorderAnimation.Sparkles:
-                AddDoubleAnimation(sb, Shape.OpacityProperty, 1.0, 0.4, TimeSpan.FromSeconds(0.3), true);
-                break;
-            case BorderAnimation.MarchingAnts:
-                shape.StrokeDashArray = new DoubleCollection { 4, 2 };
-                AddDoubleAnimation(sb, Shape.StrokeDashOffsetProperty, 0, -20, TimeSpan.FromSeconds(0.8), false);
-                break;
-            case BorderAnimation.Chase:
-                shape.StrokeDashArray = new DoubleCollection { 8, 4 };
-                AddDoubleAnimation(sb, Shape.StrokeDashOffsetProperty, 0, -30, TimeSpan.FromSeconds(1.5), false);
-                break;
-            case BorderAnimation.Rainbow:
-                if (shape.Stroke is SolidColorBrush brush)
-                {
-                    var frozen = brush.IsFrozen;
-                    if (frozen) brush = brush.Clone();
-                    shape.Stroke = brush;
-                    var colorAnim = new ColorAnimationUsingKeyFrames
-                    {
-                        Duration = new Duration(TimeSpan.FromSeconds(3)),
-                        RepeatBehavior = RepeatBehavior.Forever
-                    };
-                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Red, KeyTime.FromTimeSpan(TimeSpan.Zero)));
-                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Yellow, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(0.5))));
-                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Green, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1))));
-                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.DodgerBlue, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.5))));
-                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.MediumPurple, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2))));
-                    colorAnim.KeyFrames.Add(new LinearColorKeyFrame(Colors.Red, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.5))));
-                    Storyboard.SetTargetProperty(colorAnim, new PropertyPath("(Shape.Stroke).(SolidColorBrush.Color)"));
-                    sb.Children.Add(colorAnim);
-                }
-                break;
-            default:
-                return null;
-        }
-        return sb.Children.Count > 0 ? sb : null;
-    }
-
-    private static void AddDoubleAnimation(Storyboard sb, DependencyProperty prop,
-        double from, double to, Duration duration, bool autoReverse)
-    {
-        var anim = new DoubleAnimation(from, to, duration)
-        {
-            AutoReverse = autoReverse,
-            RepeatBehavior = RepeatBehavior.Forever
-        };
-        Storyboard.SetTargetProperty(anim, new PropertyPath(prop));
-        sb.Children.Add(anim);
-    }
-
-    private void WebcamMenu_SetBorderColor(object sender, RoutedEventArgs e)
-    {
-        if (sender is MenuItem { DataContext: SceneElement element, Tag: string color })
-            element.BorderColor = color;
-    }
-
-    private void WebcamMenu_HideInScene(object sender, RoutedEventArgs e)
-    {
-        if (sender is MenuItem { DataContext: SceneElement element })
-            element.IsVisible = false;
-    }
-
-    private void WebcamMenu_Remove(object sender, RoutedEventArgs e)
-    {
-        if (sender is MenuItem { DataContext: SceneElement element })
-            _viewModel.RemoveSourceCommand.Execute(element);
-    }
-
-    private void BackgroundMenu_ChangeCapture(object sender, RoutedEventArgs e)
-    {
-        _ = _viewModel.ChangeBackgroundCaptureAsync();
-    }
-
-    private void BackgroundMenu_RefreshCapture(object sender, RoutedEventArgs e)
-    {
-        _viewModel.RefreshBackgroundAutoCapture();
-    }
-
-    private void SourceMenu_Remove(object sender, RoutedEventArgs e)
-    {
-        if (sender is MenuItem { DataContext: SceneElement element })
-            _viewModel.RemoveSourceCommand.Execute(element);
-    }
-
-    private void OpacitySlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
-        => OpacityValueText.Text = $"{Math.Round(e.NewValue * 100)}%";
-
-    // ─── Social bar: click toggles top ⇄ bottom. KISS — the drag variant was
-    // unusable for shaky hands (jitter around the direction deadzone), so the bar
-    // rides on {Binding SocialBarTop} alone and a click flips it. ───
-    private void SocialBar_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
-    {
-        _viewModel.ToggleSocialBarPosition();
-        e.Handled = true;
-    }
-
-    private DispatcherTimer? _socialGlowTimer;
-    private double _socialGlowAngle;
-
-    private void SocialsButton_MouseEnter(object sender, MouseEventArgs e)
-    {
-        if (SocialBarElement == null) return;
-
-        // Kick the social bar to full brightness so it's immediately visible
-        var effect = SocialBarElement.Effect as DropShadowEffect;
-        if (effect != null)
-        {
-            effect.BlurRadius = 40;
-            effect.Opacity = 1.0;
-        }
-
-        // Pulse the glow so it catches the eye
-        _socialGlowAngle = 0;
-        _socialGlowTimer?.Stop();
-        _socialGlowTimer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(30) };
-        _socialGlowTimer.Tick += SocialGlowTick;
-        _socialGlowTimer.Start();
-    }
-
-    private void SocialsButton_MouseLeave(object sender, MouseEventArgs e)
-    {
-        _socialGlowTimer?.Stop();
-        _socialGlowTimer = null;
-
-        if (SocialBarElement?.Effect is DropShadowEffect effect)
-        {
-            effect.BlurRadius = 18;
-            effect.Opacity = 0.9;
-        }
-    }
-
-    private void SocialGlowTick(object? sender, EventArgs e)
-    {
-        if (SocialBarElement?.Effect is not DropShadowEffect effect) return;
-
-        _socialGlowAngle += 0.18;
-        if (_socialGlowAngle > Math.PI * 2) _socialGlowAngle -= Math.PI * 2;
-
-        // Smooth sine pulse: BlurRadius 24→48, Opacity 0.7→1.0
-        double t = (Math.Sin(_socialGlowAngle) + 1.0) / 2.0; // 0..1
-        effect.BlurRadius = 24 + t * 24;
-        effect.Opacity = 0.7 + t * 0.3;
-    }
-
-    private void Preview_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
-    {
-        if (!_viewModel.IsEditMode) return;
-        var grid = (Grid)sender;
-        var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
-        var p = toCanvas.Transform(e.GetPosition(grid));
-        var selected = _viewModel.SelectedElement;
-
-        if (selected is { } sel && IsDraggableElement(sel) && HitHandle(e.GetPosition(grid), sel))
-        {
-            _isResizing = true;
-            _resizeAspect = sel.ClipShape == ClipShape.Round ? 1 : sel.Width / Math.Max(1, sel.Height);
-            grid.CaptureMouse();
-            e.Handled = true;
-            return;
-        }
-
-        var hit = HitElement(p);
-        if (hit != null)
-        {
-            _viewModel.SelectedElement = hit;
-            _isDraggingOverlay = true;
-            _grabOffset = new Point(p.X - hit.X, p.Y - hit.Y);
-            grid.CaptureMouse();
-            e.Handled = true;
-            return;
-        }
-
-        _viewModel.SelectedElement = null;
-    }
-
-    private void Preview_MouseMove(object sender, MouseEventArgs e)
-    {
-        if (!_viewModel.IsEditMode) return;
-        if (!_isDraggingOverlay && !_isResizing) return;
-
-        var grid = (Grid)sender;
-        var toCanvas = CanvasGrid.TransformToVisual(grid).Inverse;
-        var p = toCanvas.Transform(e.GetPosition(grid));
-        var selected = _viewModel.SelectedElement;
-        if (selected == null)
-        {
-            EndPreviewDrag(grid);
-            return;
-        }
-
-        if (_isDraggingOverlay)
-        {
-            var minX = -(selected.Width - 20);
-            var maxX = 1920 - 20;
-            var minY = -(selected.Height - 20);
-            var maxY = 1080 - 20;
-            selected.X = Math.Clamp(p.X - _grabOffset.X, Math.Min(minX, maxX), Math.Max(minX, maxX));
-            selected.Y = Math.Clamp(p.Y - _grabOffset.Y, Math.Min(minY, maxY), Math.Max(minY, maxY));
-        }
-        else if (_isResizing)
-        {
-            var isWebcam = selected is WebcamSceneConfig;
-            var isRound = selected.ClipShape == ClipShape.Round;
-            var proportional = isRound || Keyboard.Modifiers.HasFlag(ModifierKeys.Shift);
-            var maxW = isWebcam ? MainViewModel.MaxWebcamWidthFor(_viewModel.StagedScene?.Name) : 1920;
-            var maxH = isWebcam ? MainViewModel.MaxWebcamHeightFor(_viewModel.StagedScene?.Name) : 1080;
-            var newW = Math.Clamp(p.X - selected.X, 32, maxW);
-            var newH = proportional ? newW / _resizeAspect : Math.Clamp(p.Y - selected.Y, 32, maxH);
-            if (proportional && newH > maxH)
-            {
-                newH = maxH;
-                newW = newH * _resizeAspect;
-            }
-            selected.Width = newW;
-            selected.Height = newH;
-        }
-    }
-
-    private void Preview_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-        => EndPreviewDrag((Grid)sender);
-
-    private void EndPreviewDrag(Grid grid)
-    {
-        if (_isDraggingOverlay || _isResizing)
-            grid.ReleaseMouseCapture();
-        _isDraggingOverlay = false;
-        _isResizing = false;
-    }
-
-    private bool HitHandle(Point mouseScreen, SceneElement element)
-    {
-        var corner = CanvasGrid.TransformToVisual(PreviewGrid).Transform(new Point(element.X + element.Width, element.Y + element.Height));
-        return Math.Abs(mouseScreen.X - corner.X) <= 20 && Math.Abs(mouseScreen.Y - corner.Y) <= 20;
-    }
-
-    private SceneElement? HitElement(Point p)
-    {
-        var scene = _viewModel.StagedScene;
-        if (scene == null) return null;
-        for (var i = scene.Elements.Count - 1; i >= 0; i--)
-        {
-            var element = scene.Elements[i];
-            if (!IsDraggableElement(element)) continue;
-            if (element is Source { IsEnabled: false }) continue;
-            if (element is WebcamSceneConfig { IsVisible: false }) continue;
-            if (p.X >= element.X && p.X <= element.X + element.Width &&
-                p.Y >= element.Y && p.Y <= element.Y + element.Height)
-                return element;
-        }
-        return null;
-    }
-
-    private void SourceNameBox_KeyDown(object sender, KeyEventArgs e)
-    {
-        if (e.Key is Key.Enter or Key.Escape)
-        {
-            CommitSourceEdit(sender);
-            e.Handled = true;
-        }
-    }
-
-    private void SourceNameBox_LostFocus(object sender, RoutedEventArgs e)
-    {
-        CommitSourceEdit(sender);
-    }
-
-    private static void CommitSourceEdit(object sender)
-    {
-        if (sender is FrameworkElement { DataContext: SceneElement element })
-            element.IsEditing = false;
-    }
-
-    // ─── List drag-to-reorder (scenes list + sources list) ───
-    private Point _dragStartPoint;
-    private int _dragIndex = -1;
-    private bool _isDragging;
-    private object? _lastHoveredItem;
-
-    private void List_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
-    {
-        var listBox = (ListBox)sender;
-        var item = FindItemContainerAt(listBox, e.GetPosition(listBox));
-        if (item == null)
-        {
-            if (ReferenceEquals(listBox, SourceList))
-                _viewModel.SelectedElement = null;
-            _dragIndex = -1;
-            return;
-        }
-        if (listBox.ItemsSource is not IList items || items.Count == 0)
-        {
-            _dragIndex = -1;
-            return;
-        }
-        _dragIndex = listBox.Items.IndexOf(item.DataContext);
-        _dragStartPoint = e.GetPosition(listBox);
-        _isDragging = false;
-        _lastHoveredItem = null;
-    }
-
-    private void List_PreviewMouseMove(object sender, MouseEventArgs e)
-    {
-        if (_dragIndex < 0) return;
-        var listBox = (ListBox)sender;
-        if (e.LeftButton != MouseButtonState.Pressed || listBox.ItemsSource is not IList items)
-        {
-            EndListDrag(listBox);
-            return;
-        }
-
-        var position = e.GetPosition(listBox);
-        if (!_isDragging)
-        {
-            if (Math.Abs(position.X - _dragStartPoint.X) < SystemParameters.MinimumHorizontalDragDistance &&
-                Math.Abs(position.Y - _dragStartPoint.Y) < SystemParameters.MinimumVerticalDragDistance)
-                return;
-            _isDragging = true;
-            listBox.CaptureMouse();
-        }
-
-        var item = FindItemContainerAt(listBox, position);
-        if (item == null) return;
-
-        var targetItem = item.DataContext;
-        if (ReferenceEquals(targetItem, items[_dragIndex]) || ReferenceEquals(targetItem, _lastHoveredItem))
-            return;
-
-        var targetIndex = listBox.Items.IndexOf(targetItem);
-        if (targetIndex < 0) return;
-
-        var dragged = items[_dragIndex];
-        items.RemoveAt(_dragIndex);
-        items.Insert(targetIndex, dragged);
-        _dragIndex = targetIndex;
-        _lastHoveredItem = targetItem;
-    }
-
-    private void List_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
-    {
-        EndListDrag((ListBox)sender);
-    }
-
-    private void EndListDrag(ListBox listBox)
-    {
-        if (_isDragging)
-            listBox.ReleaseMouseCapture();
-        _dragIndex = -1;
-        _isDragging = false;
-        _lastHoveredItem = null;
-    }
-
-    private static ListBoxItem? FindItemContainerAt(ListBox listBox, Point position)
-    {
-        var hit = listBox.InputHitTest(position) as DependencyObject;
-        while (hit != null && hit != listBox)
-        {
-            if (hit is ListBoxItem item) return item;
-            hit = VisualTreeHelper.GetParent(hit);
-        }
-        return null;
-    }
-
-    private Models.SceneElement? _snapshotElement;
-    private string _snapshotBorderColor = string.Empty;
-    private int _snapshotBorderWidth;
-    private int _snapshotTimerMinutes = 15;
-    private string? _snapshotWebUri;
-
-    private void TakeSnapshot()
-    {
-        if (_viewModel.SelectedElement is Models.Source src)
-        {
-            _snapshotElement = src;
-            _snapshotBorderColor = src.BorderColor;
-            _snapshotBorderWidth = src.BorderWidth;
-            _snapshotTimerMinutes = src.TimerMinutes;
-            _snapshotWebUri = src.WebUri;
-        }
-    }
-
-    private void WebcamBorderColorPicker_Click(object sender, RoutedEventArgs e)
-    {
-        if (_viewModel.SelectedElement is not SceneElement src) return;
-        if (sender is FrameworkElement fe && fe.ContextMenu == null)
-        {
-            var menu = new System.Windows.Controls.ContextMenu();
-            string[] colors = ["#FFFFFF", "#000000", "#FF0000", "#00FF00", "#0000FF",
-                               "#FFFF00", "#FF00FF", "#00FFFF", "#FF8800", "#8800FF",
-                               "#e94560", "#22c55e", "#3b82f6", "#f59e0b"];
-            foreach (var c in colors)
-            {
-                var item = new System.Windows.Controls.MenuItem { Header = c, ToolTip = c };
-                var brush = new System.Windows.Media.SolidColorBrush(
-                    (System.Windows.Media.Color)System.Windows.Media.ColorConverter.ConvertFromString(c));
-                item.Icon = new System.Windows.Controls.Border
-                {
-                    Width = 16, Height = 16,
-                    Background = brush,
-                    CornerRadius = new System.Windows.CornerRadius(2)
-                };
-                var color = c;
-                item.Click += (_, _) => src.BorderColor = color;
-                menu.Items.Add(item);
-            }
-            fe.ContextMenu = menu;
-        }
-        if (sender is FrameworkElement fe2)
-            fe2.ContextMenu.IsOpen = true;
-    }
-
-    private void WebcamBorderRevert_Click(object sender, RoutedEventArgs e)
-    {
-        if (_snapshotElement is Models.Source src)
-        {
-            src.BorderColor = _snapshotBorderColor;
-            src.BorderWidth = _snapshotBorderWidth;
-        }
-    }
-
-    private void WebcamBorderAccept_Click(object sender, RoutedEventArgs e)
-    {
-        if (_snapshotElement is Models.Source src)
-        {
-            _snapshotBorderColor = src.BorderColor;
-            _snapshotBorderWidth = src.BorderWidth;
-        }
-    }
-
-    private void CountdownRevert_Click(object sender, RoutedEventArgs e)
-    {
-        if (_snapshotElement is Models.Source src)
-            src.TimerMinutes = _snapshotTimerMinutes;
-    }
-
-    private void CountdownAccept_Click(object sender, RoutedEventArgs e)
-    {
-        if (_snapshotElement is Models.Source src)
-            _snapshotTimerMinutes = src.TimerMinutes;
-    }
-
-    private void WebRevert_Click(object sender, RoutedEventArgs e)
-    {
-        if (_snapshotElement is Models.Source src)
-            src.WebUri = string.Empty;
-        _snapshotWebUri = string.Empty;
-    }
-
-    private void WebAccept_Click(object sender, RoutedEventArgs e)
-    {
-        if (_snapshotElement is Models.Source src)
-            _snapshotWebUri = src.WebUri;
+        var selected = _viewModel.SelectedElement is { } s && Controls.PreviewPane.IsDraggableElement(s);
+        _previewPane.UpdateSelectionOverlay(selected);
+        _leftPanel.OnSelectionChanged(_viewModel);
     }
 }

Models/BackgroundEffect.cs

@@ -0,0 +1,11 @@
+namespace ytLive.Models;
+
+/// <summary>Per-webcam background effect (TASK 51). <see cref="Remove"/> makes everything
+/// outside the person transparent so the layers below show through; <see cref="Blur"/>
+/// blurs the background behind the person.</summary>
+public enum BackgroundEffect
+{
+    None,
+    Remove,
+    Blur,
+}

Models/BorderColorPalette.cs

@@ -0,0 +1,72 @@
+namespace ytLive.Models;
+
+/// <summary>A colour the border picker offers: its hex value and the plain-English
+/// name shown next to it (TASK 60).</summary>
+/// <param name="Hex">The hex value, e.g. <c>#e94560</c>.</param>
+/// <param name="Name">The name the creator reads, e.g. <c>Crimson</c>.</param>
+public readonly record struct NamedColor(string Hex, string Name)
+{
+    /// <summary>"Crimson (#e94560)" — the tooltip the border drop-down shows.</summary>
+    public override string ToString()
+        => string.IsNullOrEmpty(Name) ? Hex : $"{Name} ({Hex})";
+}
+
+/// <summary>The colours the webcam's border-colour drop-down offers — the SINGLE
+/// source of truth for the list and for the names.
+///
+/// <para>TASK 60 (the creator, 2026-10-21): *"in the drop down box, the #hex values are
+/// good, but add a corresponding color name/label next to the value."* The list used to
+/// be a hard-coded array in the click handler, which is why a name could not be added
+/// to it without touching the UI code.</para>
+/// </summary>
+public static class BorderColorPalette
+{
+    /// <summary>The offered colours, in menu order.</summary>
+    public static IReadOnlyList<NamedColor> All { get; } = new NamedColor[]
+    {
+        new("#FFFFFF", "White"),
+        new("#000000", "Black"),
+        new("#FF0000", "Red"),
+        new("#00FF00", "Lime"),
+        new("#0000FF", "Blue"),
+        new("#FFFF00", "Yellow"),
+        new("#FF00FF", "Magenta"),
+        new("#00FFFF", "Cyan"),
+        new("#FF8800", "Orange"),
+        new("#8800FF", "Violet"),
+        new("#e94560", "Crimson"),
+        new("#22c55e", "Emerald"),
+        new("#3b82f6", "Azure"),
+        new("#f59e0b", "Amber"),
+    };
+
+    /// <summary>The colour's name, or an **empty string** when the palette has no name
+    /// for that hex (a custom hex the creator typed) — the caller decides what to show
+    /// then, and the border field shows the hex alone.</summary>
+    public static string NameOf(string hex) => EntryFor(hex).Name;
+
+    /// <summary>The palette entry for a hex value — the palette's OWN entry (so a
+    /// drop-down bound to it matches by value), or a nameless entry for a custom hex
+    /// the creator typed, so the drop-down always has a selection (TASK 63).</summary>
+    public static NamedColor EntryFor(string hex)
+    {
+        if (string.IsNullOrWhiteSpace(hex)) return new NamedColor(string.Empty, string.Empty);
+        var trimmed = hex.Trim();
+        foreach (var colour in All)
+            if (string.Equals(colour.Hex, trimmed, StringComparison.OrdinalIgnoreCase))
+                return colour;
+        return new NamedColor(trimmed, string.Empty);
+    }
+
+    /// <summary>The colours a border drop-down offers for a given hex — the palette, plus
+    /// the custom colour the creator typed when it is not one of the palette's, so the
+    /// drop-down always has a selection (TASK 63).</summary>
+    public static IReadOnlyList<NamedColor> OptionsFor(string hex)
+    {
+        var entry = EntryFor(hex);
+        var options = new List<NamedColor>(All);
+        if (!string.IsNullOrEmpty(entry.Hex) && !All.Contains(entry))
+            options.Add(entry);
+        return options;
+    }
+}

Models/Scene.cs

@@ -72,6 +72,14 @@ public class Scene : INotifyPropertyChanged
 
     public bool IsChatScene { get; init; }
 
+    /// <summary>
+    /// Asset-table id of this scene's top-strip tile artwork. The tile is a
+    /// separate image from the scene's background: the preview pane keeps
+    /// rendering the scene's original background, the strip shows this instead.
+    /// Null = the strip falls back to the background art (creator ruling 2026-10-10).
+    /// </summary>
+    public string? ThumbnailAssetId { get; set; }
+
     private BitmapSource? _snapshot;
 
     /// <summary>

Models/SceneElement.cs

@@ -19,6 +19,17 @@ public enum BorderAnimation
     Sparkles
 }
 
+/// <summary>Whether an element's pixel content is fixed (bake once into the
+/// compositor's cached base) or changes every frame (composite each tick).
+/// See ai.md "SceneGraph component + baked-crust compositor" (TASK 31).</summary>
+public enum ElementKind
+{
+    /// <summary>Pixels never change at runtime (images, background art).</summary>
+    Static,
+    /// <summary>Pixels change every frame (webcam, live capture, chat, web source).</summary>
+    Dynamic
+}
+
 /// <summary>
 /// A thing rendered in a scene: a multi-instance Source (image/background/text)
 /// or a singleton resource's per-scene config (webcam). Carries the shared
@@ -44,6 +55,15 @@ public abstract class SceneElement : INotifyPropertyChanged
     private string _name = string.Empty;
     public string Name { get => _name; set => Set(ref _name, value); }
 
+    /// <summary>Whether this element's pixels are fixed (Static) or change every
+    /// frame (Dynamic). The compositor bakes all Static layers below the first
+    /// Dynamic layer once (see <c>SceneGraph.GetSplitPoint</c>).</summary>
+    public virtual ElementKind Kind => ElementKind.Static;
+
+    /// <summary>True only for the transient zoom layer. Gates zoom-only UI:
+    /// hidden from the layers list, never selectable/draggable in the preview.</summary>
+    public virtual bool IsZoomLayer => false;
+
     /// <summary>True only for singleton resources (webcam). Gates webcam-only UI.</summary>
     public virtual bool IsWebcam => false;
 
@@ -61,6 +81,12 @@ public abstract class SceneElement : INotifyPropertyChanged
 
     /// <summary>True only for Countdown-type sources. Gates timer properties panel.</summary>
     public virtual bool IsCountdown => false;
+
+    /// <summary>True only for AlertBox-type sources. Gates stream alerts properties panel.</summary>
+    public virtual bool IsAlertBox => false;
+    public virtual bool IsTextOverlay => false;
+    public virtual bool IsMediaSource => false;
+    public virtual bool IsLiveCapture => false;
     public virtual bool IsBackground { get; set; }
 
     private bool _useDefaultBackground = true;
@@ -88,13 +114,45 @@ public abstract class SceneElement : INotifyPropertyChanged
     public bool IsEditing { get => _isEditing; set => Set(ref _isEditing, value); }
 
     private ClipShape _clipShape = ClipShape.Traditional;
-    public ClipShape ClipShape
+    // Virtual so a derived element can CONSTRAIN the shape (the webcam is
+    // rect-only in the vertical tier's Chat layout — TASK 57) instead of every
+    // writer re-implementing the rule.
+    public virtual ClipShape ClipShape
     {
         get => _clipShape;
         set
         {
             if (Set(ref _clipShape, value))
-                Raise(nameof(ShapeButtonText));
+            {
+                Raise(nameof(IsRectShape));
+                Raise(nameof(IsRoundShape));
+            }
+        }
+    }
+
+    /// <summary>True when the element's clip is the plain rectangle — the shape a
+    /// camera has when none was ever picked (TASK 59: the properties panel shows
+    /// the shape as a CHOICE, and Rect is the selected default).</summary>
+    public bool IsRectShape
+    {
+        get => ClipShape != ClipShape.Round;
+        set
+        {
+            // Round -> rect (restores the pre-round rect, like the toggle does).
+            if (value && ClipShape == ClipShape.Round) ToggleClipShape();
+            Raise(nameof(IsRectShape));
+        }
+    }
+
+    /// <summary>True when the element's clip is a circle (TASK 59).</summary>
+    public bool IsRoundShape
+    {
+        get => ClipShape == ClipShape.Round;
+        set
+        {
+            // Rect -> round (stores the pre-round rect, like the toggle does).
+            if (value && ClipShape != ClipShape.Round) ToggleClipShape();
+            Raise(nameof(IsRoundShape));
         }
     }
 
@@ -107,7 +165,7 @@ public abstract class SceneElement : INotifyPropertyChanged
     public double? RectWidth { get => _rectWidth; set => Set(ref _rectWidth, value); }
     public double? RectHeight { get => _rectHeight; set => Set(ref _rectHeight, value); }
 
-    public void ToggleClipShape()
+    public virtual void ToggleClipShape()
     {
         if (ClipShape == ClipShape.Traditional)
         {
@@ -144,7 +202,6 @@ public abstract class SceneElement : INotifyPropertyChanged
 
     public double MirrorScale => IsMirrored ? -1 : 1;
     public string MirrorButtonText => IsMirrored ? "Unmirror" : "Mirror";
-    public string ShapeButtonText => ClipShape == ClipShape.Round ? "Rect" : "Round";
 
     // Live camera frames: the shared WriteableBitmap owned by CameraManager.
     private WriteableBitmap? _videoImageSource;
@@ -161,15 +218,18 @@ public abstract class SceneElement : INotifyPropertyChanged
     /// <summary>What the preview shows: live frames (webcam) or a static image (sources).</summary>
     public abstract ImageSource? DisplaySource { get; }
 
-    // Position/transform (per-scene usage)
+    // Position/transform (per-scene usage). The geometry setters are virtual so
+    // a derived element can CONSTRAIN them (the webcam clamps itself into the
+    // vertical tier's band — TASK 57) instead of every writer re-implementing
+    // the rule.
     private double _x;
-    public double X { get => _x; set => Set(ref _x, value); }
+    public virtual double X { get => _x; set => Set(ref _x, value); }
 
     private double _y;
-    public double Y { get => _y; set => Set(ref _y, value); }
+    public virtual double Y { get => _y; set => Set(ref _y, value); }
 
     private double _width;
-    public double Width
+    public virtual double Width
     {
         get => _width;
         set
@@ -180,7 +240,7 @@ public abstract class SceneElement : INotifyPropertyChanged
     }
 
     private double _height;
-    public double Height
+    public virtual double Height
     {
         get => _height;
         set
@@ -207,10 +267,26 @@ public abstract class SceneElement : INotifyPropertyChanged
             {
                 Raise(nameof(HasBorder));
                 Raise(nameof(BorderBrush));
+                Raise(nameof(BorderColorEntry));
+                Raise(nameof(BorderColorOptions));
             }
         }
     }
 
+    /// <summary>The border colour as the drop-down sees it: the palette's entry for the
+    /// current hex — with its NAME — or a nameless entry for a custom hex the creator
+    /// typed. Setting it writes the hex back (TASK 63).</summary>
+    public NamedColor BorderColorEntry
+    {
+        get => BorderColorPalette.EntryFor(BorderColor);
+        set => BorderColor = value.Hex;
+    }
+
+    /// <summary>The colours the border drop-down offers — the palette, plus the custom
+    /// colour the creator typed (so the drop-down always has a selection) (TASK 63).</summary>
+    public IReadOnlyList<NamedColor> BorderColorOptions
+        => BorderColorPalette.OptionsFor(BorderColor);
+
     private double _borderOpacity = 1.0;
     public double BorderOpacity
     {

Models/Source.cs

@@ -13,7 +13,10 @@ public enum SourceType
     Countdown,
     WebSource,
     ChatBox,
-    MediaSource
+    MediaSource,
+    /// <summary>The designated alert zone: the six monetization events play their
+    /// unique celebration animations here (OBS alert-box equivalent, native).</summary>
+    AlertBox
 }
 
 /// <summary>Distinguishes how a media source presents its content (TASK 21).</summary>
@@ -37,6 +40,19 @@ public enum ClipShape
     Round
 }
 
+/// <summary>How an alert box presents its announcement strip (TASK 47). The strip is
+/// the full-width pill naming the event ("Viewer — Super Chat · $12.34").</summary>
+public enum AlertDisplayMethod
+{
+    /// <summary>Marquee: the pill scrolls across the top edge, paced so the text is
+    /// read <see cref="AlertOverlayLayer.TickerReadsPerAlert"/> times per alert.</summary>
+    TickerScroll,
+    /// <summary>Pulse: the static pill blinks on and off for the whole alert.</summary>
+    Flash,
+    /// <summary>Static: the pill sits centred and still for the whole alert.</summary>
+    Solid
+}
+
 /// <summary>
 /// A multi-instance scene object: image/background/text (screen/window later).
 /// The webcam is NOT a Source — it's a singleton resource whose per-scene usage
@@ -57,13 +73,20 @@ public class Source : SceneElement
                 Raise(nameof(IsLiveCapture));
                 Raise(nameof(DisplaySource));
                 Raise(nameof(IsWebSource));
+                Raise(nameof(IsTextOverlay));
             }
         }
     }
 
-    public override bool IsDraggable => Type is SourceType.Image or SourceType.WebSource or SourceType.ChatBox;
+    public override bool IsDraggable => Type is SourceType.Image or SourceType.WebSource or SourceType.ChatBox or SourceType.AlertBox;
+
+    /// <summary>Live captures, chat, web sources and media are dynamic; static art is fixed.</summary>
+    public override ElementKind Kind => Type is SourceType.DisplayCapture or SourceType.WindowCapture
+        or SourceType.ChatBox or SourceType.WebSource or SourceType.MediaSource or SourceType.AlertBox
+        ? ElementKind.Dynamic : ElementKind.Static;
 
     public override bool IsWebSource => Type == SourceType.WebSource;
+    public override bool IsTextOverlay => Type == SourceType.TextOverlay;
 
     /// <summary>The permanent scene background (live desktop/game capture). Never removable/reorderable.</summary>
     private bool _isBackground;
@@ -89,7 +112,7 @@ public class Source : SceneElement
     private string? _captureKey;
     public string? CaptureKey { get => _captureKey; set => Set(ref _captureKey, value); }
 
-    public bool IsLiveCapture => Type is SourceType.DisplayCapture or SourceType.WindowCapture;
+    public override bool IsLiveCapture => Type is SourceType.DisplayCapture or SourceType.WindowCapture;
 
     // Image (asset stored in the layout database)
     private string? _assetId;
@@ -113,7 +136,7 @@ public class Source : SceneElement
 
     public override ImageSource? DisplaySource => IsLiveCapture
         ? (VideoImageSource ?? _imageSource)
-        : (Type is SourceType.ChatBox or SourceType.WebSource ? VideoImageSource : _imageSource);
+        : (Type is SourceType.ChatBox or SourceType.WebSource or SourceType.MediaSource or SourceType.AlertBox ? VideoImageSource : _imageSource);
 
     public override bool IsImageSource => Type == SourceType.Image;
 
@@ -169,7 +192,55 @@ public class Source : SceneElement
         set => Set(ref _mediaPlaybackState, value);
     }
 
-    public bool IsMediaSource => Type == SourceType.MediaSource;
+    public override bool IsMediaSource => Type == SourceType.MediaSource;
+
+    // Alert video config (TASK 47): the shipped default clip lives in the Asset
+    // table (seeded like image assets); the creator's replacement is a FILE PATH
+    // reference only — never into the DB (creator ruling, 2026-09-26). Runtime
+    // order: replacement path exists → DB default → six celebration animations.
+    private string? _alertVideoAssetId;
+    public string? AlertVideoAssetId
+    {
+        get => _alertVideoAssetId;
+        set => Set(ref _alertVideoAssetId, value);
+    }
+
+    private string? _alertVideoPath;
+    public string? AlertVideoPath
+    {
+        get => _alertVideoPath;
+        set => Set(ref _alertVideoPath, value);
+    }
+
+    private bool _alertUseDefaultVideo = true;
+    public bool AlertUseDefaultVideo
+    {
+        get => _alertUseDefaultVideo;
+        set => Set(ref _alertUseDefaultVideo, value);
+    }
+
+    private bool _alertShowTicker = true;
+    public bool AlertShowTicker
+    {
+        get => _alertShowTicker;
+        set => Set(ref _alertShowTicker, value);
+    }
+
+    private double _alertVideoVolume = 1.0;
+    public double AlertVideoVolume
+    {
+        get => _alertVideoVolume;
+        set => Set(ref _alertVideoVolume, Math.Clamp(value, 0.0, 1.0));
+    }
+
+    private AlertDisplayMethod _alertDisplayMethod = AlertDisplayMethod.TickerScroll;
+    public AlertDisplayMethod AlertDisplayMethod
+    {
+        get => _alertDisplayMethod;
+        set => Set(ref _alertDisplayMethod, value);
+    }
+
+    public override bool IsAlertBox => Type == SourceType.AlertBox;
 
     // Chat box config (TASK 3.18)
     private double _chatFontSize = 16;

Models/VerticalCameraLayout.cs

@@ -0,0 +1,85 @@
+using System.Windows;
+
+namespace ytLive.Models;
+
+/// <summary>
+/// The vertical (9:16) tier's camera rules — TASK 57, the "vv" feature.
+///
+/// The vertical tier is a centred band crop of the SAME 1920×1080 master the
+/// 16:9 tiers use, so a camera placed for 16:9 lands outside the cropped
+/// window and vanishes from the vertical output. The vertical tier therefore
+/// keeps its OWN placement per scene: a small tile inside the band, snapped to
+/// one of six spots — the band splits into a top and a bottom half, each with
+/// a left, a centre and a right slot.
+///
+/// Geometry only: the preview and the compositor both read the element's own
+/// X/Y/W/H + ClipShape, so the placement is resolved by swapping those values
+/// when the tier changes. No render-path change.
+/// </summary>
+public static class VerticalCameraLayout
+{
+    /// <summary>The vertical tier's camera tile over the master frame —
+    /// 270×152 master px = 480×270 in the 1080×1920 output.</summary>
+    public const double TileWidth = 270;
+    public const double TileHeight = 152;
+
+    /// <summary>How far the tile keeps from the band's outer edge — the app's
+    /// own placement margin (32 master px) used by the default webcam spot.</summary>
+    public const double Inset = 32;
+
+    /// <summary>True for the portrait tier (the vertical 1080×1920 one).</summary>
+    public static bool IsVerticalTier(QualityOption quality) => quality.Height > quality.Width;
+
+    /// <summary>The half of the band a tile lives in — top or bottom.</summary>
+    public static Rect AreaFor(Rect band, bool bottom)
+        => new(band.Left, bottom ? band.Top + band.Height / 2 : band.Top, band.Width, band.Height / 2);
+
+    /// <summary>The largest a camera may be inside the band: one whole area.</summary>
+    public static (double Width, double Height) MaxSizeFor(Rect band)
+        => (band.Width, band.Height / 2);
+
+    /// <summary>True when a camera is wide enough to fill one whole area of the
+    /// band — the "enlarged" Chat layout (one 607×540 area).</summary>
+    public static bool FillsArea(Rect band, double width) => width >= band.Width - 1;
+
+    /// <summary>The two sizes a camera may take in the vertical tier's Chat
+    /// layout: the small tile (normal) or one whole area (enlarged). Returns
+    /// the one nearer the requested width, so the resize handle snaps between
+    /// them instead of taking any size in between.</summary>
+    public static (double Width, double Height) SizeFor(Rect band, double requestedWidth)
+    {
+        var (areaWidth, areaHeight) = MaxSizeFor(band);
+        return Math.Abs(requestedWidth - TileWidth) <= Math.Abs(requestedWidth - areaWidth)
+            ? (TileWidth, TileHeight)
+            : (areaWidth, areaHeight);
+    }
+
+    /// <summary>
+    /// The spot a tile snaps to: the area (top/bottom) and the column
+    /// (left/centre/right) its centre falls in, then the tile's top-left for
+    /// that spot — inset from the band's outer edge, and never outside the band
+    /// (a tile wider than the inset eats it).
+    /// </summary>
+    public static (double X, double Y) SpotFor(Rect band, double width, double height, double centreX, double centreY)
+    {
+        var bottom = centreY >= band.Top + band.Height / 2;
+        var area = AreaFor(band, bottom);
+        var third = area.Width / 3;
+
+        double x;
+        if (centreX < area.Left + third) x = area.Left + Inset;
+        else if (centreX < area.Left + 2 * third) x = area.Left + (area.Width - width) / 2;
+        else x = area.Right - Inset - width;
+
+        var y = bottom ? area.Bottom - Inset - height : area.Top + Inset;
+
+        x = Math.Clamp(x, band.Left, Math.Max(band.Left, band.Right - width));
+        y = Math.Clamp(y, band.Top, Math.Max(band.Top, band.Bottom - height));
+        return (x, y);
+    }
+
+    /// <summary>The default tile spot: the bottom-right corner of the band —
+    /// the same corner the 16:9 default webcam placement uses.</summary>
+    public static (double X, double Y) DefaultSpot(Rect band, double width, double height)
+        => SpotFor(band, width, height, band.Right, band.Bottom);
+}

Models/WebcamSceneConfig.cs

@@ -1,3 +1,4 @@
+using System.Windows;
 using System.Windows.Media;
 
 namespace ytLive.Models;
@@ -13,5 +14,223 @@ public class WebcamSceneConfig : SceneElement
     public string WebcamId { get; init; } = string.Empty;
     public override bool IsWebcam => true;
     public override bool IsDraggable => true;
+    public override ElementKind Kind => ElementKind.Dynamic;
     public override ImageSource? DisplaySource => VideoImageSource;
+
+    private BackgroundEffect _backgroundEffect = BackgroundEffect.None;
+    /// <summary>TASK 51: this scene's background effect for the webcam (persisted).</summary>
+    public BackgroundEffect BackgroundEffect
+    {
+        get => _backgroundEffect;
+        set
+        {
+            if (!Set(ref _backgroundEffect, value)) return;
+            Raise(nameof(RemoveBackground));
+            Raise(nameof(BlurBackground));
+            Raise(nameof(HasBackgroundEffect));
+        }
+    }
+
+    /// <summary>True while Remove or Blur is on — shows the strength slider.</summary>
+    public bool HasBackgroundEffect => BackgroundEffect != BackgroundEffect.None;
+
+    private double _backgroundStrength = 0.5;
+    /// <summary>TASK 51: 0..1 — Blur amount, or Remove's edge softness (persisted).</summary>
+    public double BackgroundStrength
+    {
+        get => _backgroundStrength;
+        set => Set(ref _backgroundStrength, Math.Clamp(value, 0, 1));
+    }
+
+    /// <summary>Pill-switch surface: Remove and Blur behave like radio buttons — turning one
+    /// on turns the other off; turning the active one off means <see cref="BackgroundEffect.None"/>.</summary>
+    public bool RemoveBackground
+    {
+        get => BackgroundEffect == BackgroundEffect.Remove;
+        set => BackgroundEffect = value ? BackgroundEffect.Remove
+            : BackgroundEffect == BackgroundEffect.Remove ? BackgroundEffect.None : BackgroundEffect;
+    }
+
+    /// <inheritdoc cref="RemoveBackground"/>
+    public bool BlurBackground
+    {
+        get => BackgroundEffect == BackgroundEffect.Blur;
+        set => BackgroundEffect = value ? BackgroundEffect.Blur
+            : BackgroundEffect == BackgroundEffect.Blur ? BackgroundEffect.None : BackgroundEffect;
+    }
+
+    // ─── Vertical (9:16) tier placement (TASK 57, the "vv" feature) ────────
+    // The vertical tier is a centred band crop of the same master frame, so the
+    // 16:9 placement lands outside the cropped window and the camera vanishes
+    // from the vertical output. The vertical tier therefore keeps its OWN
+    // position, size and shape per scene, stored here and resolved when the
+    // tier changes; switching back to 16:9 restores the desktop layout exactly.
+
+    /// <summary>The vertical placement's X (null until the scene has one).</summary>
+    public double? VerticalX { get; set; }
+
+    /// <summary>The vertical placement's Y (null until the scene has one).</summary>
+    public double? VerticalY { get; set; }
+
+    /// <summary>The vertical placement's width (null until the scene has one).</summary>
+    public double? VerticalWidth { get; set; }
+
+    /// <summary>The vertical placement's height (null until the scene has one).</summary>
+    public double? VerticalHeight { get; set; }
+
+    /// <summary>The vertical placement's clip shape (circle or rect) — the
+    /// creator's own choice per scene, independent of the 16:9 shape.</summary>
+    public ClipShape? VerticalClipShape { get; set; }
+
+    /// <summary>The vertical placement's pre-Round rect (so a Round tile
+    /// restores its aspect on toggle-back, like the 16:9 one does).</summary>
+    public double? VerticalRectWidth { get; set; }
+
+    /// <inheritdoc cref="VerticalRectWidth"/>
+    public double? VerticalRectHeight { get; set; }
+
+    /// <summary>True once this scene has a vertical placement of its own.</summary>
+    public bool HasVerticalLayout => VerticalX is not null;
+
+    /// <summary>True while the vertical placement is the LIVE geometry (the
+    /// element's own X/Y/W/H). The 16:9 layout is parked in
+    /// <see cref="LandscapeX"/> and friends until the tier switches back.</summary>
+    public bool VerticalLayoutLive { get; private set; }
+
+    /// <summary>True while the vertical placement must stay RECT — the Chat
+    /// scene's vertical layout (the creator's table: "vv · Chat = rect only, no
+    /// circle option"). The circle is not offered there, so the shape cannot
+    /// become Round by any writer.</summary>
+    public bool VerticalShapeLocked { get; internal set; }
+
+    /// <summary>The vertical tier's band over the master frame (transient — the
+    /// VM sets it when the tier changes). While the vertical placement is live
+    /// the camera's geometry is clamped to it: outside the band is invisible.</summary>
+    public Rect VerticalBand { get; set; } = Rect.Empty;
+
+    // The parked 16:9 layout — meaningful only while the vertical placement is
+    // live (it is the 16:9 geometry the tier switch restores).
+    public double LandscapeX { get; private set; }
+    public double LandscapeY { get; private set; }
+    public double LandscapeWidth { get; private set; }
+    public double LandscapeHeight { get; private set; }
+    public ClipShape LandscapeClipShape { get; private set; }
+    public double? LandscapeRectWidth { get; private set; }
+    public double? LandscapeRectHeight { get; private set; }
+
+    /// <summary>Parks the live (16:9) layout and brings a vertical placement
+    /// in. The vertical placement becomes the live geometry from here on.</summary>
+    public void BeginVerticalLayout(double x, double y, double width, double height, ClipShape clipShape)
+    {
+        LandscapeX = X;
+        LandscapeY = Y;
+        LandscapeWidth = Width;
+        LandscapeHeight = Height;
+        LandscapeClipShape = ClipShape;
+        LandscapeRectWidth = RectWidth;
+        LandscapeRectHeight = RectHeight;
+
+        VerticalLayoutLive = true;
+        Width = width;
+        Height = height;
+        X = x;
+        Y = y;
+        ClipShape = clipShape;
+        RectWidth = VerticalRectWidth;
+        RectHeight = VerticalRectHeight;
+    }
+
+    /// <summary>Restores the parked 16:9 layout — the tier switched back.</summary>
+    public void EndVerticalLayout()
+    {
+        if (!VerticalLayoutLive) return;
+
+        // The vertical placement is the creator's own — keep it, so switching
+        // back and forth does not lose where they put it.
+        CommitLiveLayoutToVertical();
+
+        VerticalLayoutLive = false;
+        Width = LandscapeWidth;
+        Height = LandscapeHeight;
+        X = LandscapeX;
+        Y = LandscapeY;
+        ClipShape = LandscapeClipShape;
+        RectWidth = LandscapeRectWidth;
+        RectHeight = LandscapeRectHeight;
+    }
+
+    /// <summary>Copies the live geometry into the stored vertical placement, so
+    /// the stored copy never lags the live one (the save path calls this).</summary>
+    public void CommitLiveLayoutToVertical()
+    {
+        VerticalX = X;
+        VerticalY = Y;
+        VerticalWidth = Width;
+        VerticalHeight = Height;
+        VerticalClipShape = ClipShape;
+        VerticalRectWidth = RectWidth;
+        VerticalRectHeight = RectHeight;
+    }
+
+    // The Chat scene's vertical layout is rect-only (the creator's table, the
+    // circle option is not offered there). Locking the SHAPE property — not
+    // just the toggle — means no writer can slip a Round camera in: the
+    // toggle, the shape button and the placement swap all go through here.
+    public override ClipShape ClipShape
+    {
+        get => base.ClipShape;
+        set => base.ClipShape = VerticalShapeLocked ? ClipShape.Traditional : value;
+    }
+
+    public override void ToggleClipShape()
+    {
+        if (VerticalShapeLocked)
+        {
+            ClipShape = ClipShape.Traditional;
+            return;
+        }
+        base.ToggleClipShape();
+    }
+
+    // The geometry is clamped into the band while the vertical placement is
+    // live — a camera outside the cropped window is a camera the viewers never
+    // see, and every writer (drag, resize handle, the properties fields) goes
+    // through these setters.
+    public override double X
+    {
+        get => base.X;
+        set => base.X = ClampToBand(value, base.Width, vertical: true);
+    }
+
+    public override double Y
+    {
+        get => base.Y;
+        set => base.Y = ClampToBand(value, base.Height, vertical: false);
+    }
+
+    public override double Width
+    {
+        get => base.Width;
+        set => base.Width = VerticalLayoutLive && !VerticalBand.IsEmpty
+            ? Math.Min(value, VerticalBand.Width)
+            : value;
+    }
+
+    public override double Height
+    {
+        get => base.Height;
+        set => base.Height = VerticalLayoutLive && !VerticalBand.IsEmpty
+            ? Math.Min(value, VerticalBand.Height / 2)
+            : value;
+    }
+
+    private double ClampToBand(double value, double size, bool vertical)
+    {
+        if (!VerticalLayoutLive || VerticalBand.IsEmpty) return value;
+        var band = VerticalBand;
+        var min = vertical ? band.Left : band.Top;
+        var max = vertical ? band.Right - size : band.Bottom - size;
+        if (max < min) return min;
+        return Math.Clamp(value, min, max);
+    }
 }

Models/WindowInfo.cs

@@ -0,0 +1,27 @@
+namespace ytLive.Models;
+
+/// <summary>One user-visible open window offered by the "Capture Window…"
+/// submenu. Carries its owning process name for disambiguation and the raw
+/// HWND that becomes the "window:&lt;hwnd&gt;" capture key.</summary>
+public sealed class WindowInfo
+{
+    public WindowInfo(string title, string processName, long hwnd, int processId)
+    {
+        Title = title;
+        ProcessName = processName;
+        Hwnd = hwnd;
+        ProcessId = processId;
+    }
+
+    public string Title { get; }
+    public string ProcessName { get; }
+    public long Hwnd { get; }
+    public int ProcessId { get; }
+
+    /// <summary>Menu label: "Title — ProcessName" (e.g. "bash — WindowsTerminal").</summary>
+    public string Label => $"{Title} — {ProcessName}";
+
+    /// <summary>The capture key fed to the screen-capture factory
+    /// ("window:&lt;hwnd&gt;").</summary>
+    public string CaptureKey => $"window:0x{Hwnd:X}";
+}

Models/YouTube.cs

@@ -18,6 +18,21 @@ public record ReusableStream(string Id, string IngestionAddress, string StreamNa
     public string RtmpUrl => $"{IngestionAddress}/{StreamName}";
 }
 
+/// <summary>The six monetization events YouTube's live chat feed emits (the ONLY
+/// native event stream there is — free subscribers produce no event). Each kind
+/// drives its own celebration animation in the AlertBox. <c>None</c> = a normal
+/// chat row: it never enqueues an alert (subscriber mentions stay chat rows).</summary>
+public enum ChatEventKind
+{
+    None,
+    SuperChat,
+    SuperSticker,
+    NewMember,
+    MemberGift,
+    GiftReceived,
+    MemberMilestone,
+}
+
 public class ChatMessage
 {
     public string Id { get; init; } = Guid.NewGuid().ToString();
@@ -29,6 +44,31 @@ public class ChatMessage
     public bool IsSuperChat { get; set; }
     public double SuperChatAmount { get; set; }
     public string? SuperChatCurrency { get; set; }
+
+    /// <summary>YouTube's own pre-rendered amount ("$12.34") — preferred over
+    /// recomposing amount+currency ourselves, which mangles non-dollar locales.</summary>
+    public string? SuperChatDisplayString { get; set; }
+
     public bool IsMember { get; set; }
     public string? MembershipLevel { get; set; }
+
+    public ChatEventKind Kind { get; set; }
+
+    public string? SuperStickerDescription { get; set; }
+
+    /// <summary>membershipGiftingEvent: how many memberships were bought.</summary>
+    public int GiftNewMembersCount { get; set; }
+
+    /// <summary>giftMembershipReceivedEvent: who gifted this one.</summary>
+    public string? GifterName { get; set; }
+
+    /// <summary>memberMilestoneChatEvent: streak months (0 = YouTube didn't
+    /// expose a count — the animation falls back to the message text).</summary>
+    public int MilestoneMonths { get; set; }
+
+    /// <summary>TASK 41: the Test Stream dock injects synthetic member / SuperChat /
+    /// subscriber events locally (YouTube's insert API only supports text), so the
+    /// buffer can label them honestly — simulated events never reach YouTube.</summary>
+    public bool IsSimulated { get; set; }
+    public bool IsPinned { get; set; }
 }

Models/YppStatSnapshot.cs

@@ -0,0 +1,17 @@
+namespace ytLive.Models;
+
+/// <summary>One captured snapshot of a connected channel's YPP-relevant numbers
+/// (TASK 39). Appended on every refresh and archived in SQLite so a later slice
+/// can compute velocity/(de)acceleration/ETA from the history.</summary>
+public sealed class YppStatSnapshot
+{
+    public DateTime CapturedAtUtc { get; set; }
+    public long SubscriberCount { get; set; }
+    public long VideoCount { get; set; }
+    public long TotalViews { get; set; }
+    public int UploadsLast90Days { get; set; }
+    public bool CommunityGuidelinesGoodStanding { get; set; }
+    public bool CopyrightStrikesGoodStanding { get; set; }
+    public bool ContentIdClaimsGoodStanding { get; set; }
+    public bool OverallGoodStanding { get; set; }
+}

Models/YppThresholds.cs

@@ -0,0 +1,31 @@
+namespace ytLive.Models;
+
+/// <summary>YPP eligibility thresholds as versioned, date-aware DATA — never
+/// constants (ai.md "Journey tracker"). Tier 1 (fan funding) is time-invariant;
+/// Tier 2 (ad revenue) doubles its long-form-hours and Shorts-view bars for NEW
+/// applicants after 2027-02-01. Hardcoding the pre-2027 numbers would show the
+/// wrong ETA once the doubling lands, so callers resolve the active Tier 2
+/// threshold through <see cref="Tier2For"/>.</summary>
+public static class YppThresholds
+{
+    public sealed record TierThreshold(string Name, long Subscribers, long WatchHours, long ShortsViews);
+
+    /// <summary>The date the Tier-2 ad-revenue bars double for new applicants.</summary>
+    public static readonly DateTime Tier2DoublingDate = new(2027, 2, 1);
+
+    /// <summary>Fan-funding tier (before the full ad/YouTube Premium revenue tier).</summary>
+    public static TierThreshold Tier1 { get; } = new("Fan funding", 500, 3_000, 3_000_000);
+
+    /// <summary>The Tier-2 bar for a given point in time — 4,000h / 10M Shorts
+    /// before the doubling date, 8,000h / 20M Shorts on or after it.</summary>
+    public static TierThreshold Tier2For(DateTime when) => when >= Tier2DoublingDate
+        ? new TierThreshold("Ad revenue", 1_000, 8_000, 20_000_000)
+        : new TierThreshold("Ad revenue", 1_000, 4_000, 10_000_000);
+
+    /// <summary>The currently-active Tier-2 threshold (resolved against today).</summary>
+    public static TierThreshold Tier2Now => Tier2For(DateTime.UtcNow);
+
+    /// <summary>Valid public long-form uploads required in the trailing 90 days
+    /// to keep each tier route eligible.</summary>
+    public const int UploadsRequiredPer90Days = 3;
+}

Models/ZoomSceneElement.cs

@@ -0,0 +1,36 @@
+using System.Windows.Media;
+
+namespace ytLive.Models;
+
+/// <summary>
+/// The transient zoom layer. It is a real scene element, but a special one: while
+/// active the SceneCompositor draws it LAST (layer n+1, above everything) as a live
+/// 2x view of a FIXED capture window (the box/2 region centred on where the creator
+/// clicked), sampled from the just-composited frame — so it captures ALL layers and
+/// keeps showing the same content no matter where the box is dragged (creator ruling
+/// 2026-10-08). Its X/Y/W/H are the movable BOX placement; CaptureX/CaptureY is the
+/// anchored capture window. While inactive it is an invisible placeholder that is
+/// never persisted (LayoutStore hand-rolls only Source/WebcamSceneConfig rows) — the
+/// VM re-inserts it on load and on scene creation, mirroring how backgrounds heal.
+/// </summary>
+public sealed class ZoomSceneElement : SceneElement
+{
+    /// <summary>True only while a zoom box is live; flips Kind so the layer leaves
+    /// the baked static base and composites per-frame.</summary>
+    public bool IsZoomActive { get; set; }
+
+    /// <summary>Master-space top-left of the fixed capture window. Set once by
+    /// <c>ActivateZoom</c>; moving the box must never touch it.</summary>
+    public double CaptureX { get; set; }
+    public double CaptureY { get; set; }
+
+    public override ElementKind Kind => IsZoomActive ? ElementKind.Dynamic : ElementKind.Static;
+
+    public override bool IsZoomLayer => true;
+
+    public override bool IsDraggable => false;
+
+    /// <summary>Never rendered by the element template or the resolver — the preview
+    /// magnifier (ZoomBox) and the output compositor's zoom pass own its pixels.</summary>
+    public override ImageSource? DisplaySource => null;
+}

Models/ZoomShape.cs

@@ -0,0 +1,8 @@
+namespace ytLive.Models;
+
+public enum ZoomShape
+{
+    Circle,
+    VerticalRectangle,
+    HorizontalRectangle
+}

Models/ZoomState.cs

@@ -0,0 +1,27 @@
+using System;
+
+namespace ytLive.Models;
+
+public class ZoomState
+{
+    public bool IsActive { get; set; }
+    public double X { get; set; }
+    public double Y { get; set; }
+    public double Width { get; set; }
+    public double Height { get; set; }
+
+    /// <summary>Master-space top-left of the FIXED capture window (the box/2 region
+    /// centred on the click). The box can be dragged anywhere; this never changes —
+    /// the box always shows this same region magnified 2x (creator ruling 2026-10-08).</summary>
+    public double CaptureX { get; set; }
+    public double CaptureY { get; set; }
+
+    public bool IsMoving { get; set; }
+    public double GrabOffsetX { get; set; }
+    public double GrabOffsetY { get; set; }
+
+    public double Left => X;
+    public double Top => Y;
+    public double Right => X + Width;
+    public double Bottom => Y + Height;
+}

Models/index.md

@@ -7,14 +7,18 @@ Plain data types. No logic beyond what a property can carry. See
 |------|---------|
 | `Scene.cs` | A scene: `Name`, `IsHidden`, `IsChatScene`, `IsEditing`, **`HasBackdrop`** (Live-only policy flag, default off — only the canonical Live scene has one, see `SceneCatalog`), `Elements` collection (images + webcam config), `WebcamConfig` accessor |
 | `SceneCatalog.cs` | The five canonical scenes (Starting/Live/BRB/Chat/Ending) — the product, by name: `All`, `IsCanonical`, `Is(name, canonical)` (case-insensitive trim), `IsChat`, `HasBackdrop(name)` (true only for Live). Drives the empty-DB seed, the "+" missing-scenes menu, and `MainViewModel.EnforceBackdropPolicy` |
-| `Source.cs` | A source: `SourceType` enum (DisplayCapture/WindowCapture/Background/Image/TextOverlay — **Webcam removed**), `X`/`Y`/`Width`/`Height`, `Opacity`, `IsEnabled`, `ImageSource` (static) / `VideoImageSource` (live frames), `DisplaySource` (`IsLiveCapture` → video, else static), `ClipShape` enum (Traditional/Round), `IsMirrored` + `MirrorScale`, `MirrorButtonText`/`ShapeButtonText`, asset identity, `IsImageSource` (XAML binds this, never `Type`), **backdrop surface**: `IsBackdrop` (permanent bottom layer, never removable), `CaptureKey` (persisted `monitor:<n>`/`window:<hwnd>`/`picker:<name>`), `IsLiveCapture` (`Type` is Display/WindowCapture) |
-| `SceneElement.cs` | Base for anything placeable in a scene: shared layout/clip/mirror/border surface, `virtual IsWebcam`/`virtual IsImageSource`; `ToggleClipShape` + persisted `RectWidth`/`RectHeight` (pre-Round rect so round→rect restores after reload) |
+| `Source.cs` | A source: `SourceType` enum (DisplayCapture/WindowCapture/Background/Image/TextOverlay/ChatBox/Countdown/WebSource/MediaSource/**AlertBox (TASK 43 — the celebration zone, one per layout)** — **Webcam removed**), `X`/`Y`/`Width`/`Height`, `Opacity`, `IsEnabled`, `ImageSource` (static) / `VideoImageSource` (live frames), `DisplaySource` (`IsLiveCapture` → video, else static), `ClipShape` enum (Traditional/Round), `IsMirrored` + `MirrorScale`, `MirrorButtonText`, asset identity, `IsImageSource` (XAML binds this, never `Type`), **backdrop surface**: `IsBackdrop` (permanent bottom layer, never removable), `CaptureKey` (persisted `monitor:<n>`/`window:<hwnd>`/`picker:<name>`), `IsLiveCapture` (`Type` is Display/WindowCapture) |
+| `SceneElement.cs` | Base for anything placeable in a scene: shared layout/clip/mirror/border surface, `virtual IsWebcam`/`virtual IsImageSource`/`virtual IsZoomLayer` (TASK 52); `ToggleClipShape` + persisted `RectWidth`/`RectHeight` (pre-Round rect so round→rect restores after reload); **TASK 57:** the geometry setters (`X`/`Y`/`Width`/`Height`) are `virtual` so a derived element can CONSTRAIN every write (the webcam clamps itself into the vertical tier's band) instead of every writer re-implementing the rule; `ClipShape` + `ToggleClipShape()` are `virtual` too, so a derived element can CONSTRAIN the shape (the Chat scene's vertical camera is rect-only); **TASK 59:** `IsRectShape`/`IsRoundShape` — the shape as a CHOICE (the properties panel shows Rect | Circle with Rect selected by default), each a settable bool whose setter flips the shape through `ToggleClipShape()` and always re-raises, so the UI snaps back when a write is refused; **TASK 63:** `BorderColorEntry` (the palette entry for the current border colour — hex + NAME, a nameless entry for a custom hex; setting it writes the hex back) and `BorderColorOptions` (the palette + that entry), both raised when `BorderColor` changes — the drop-down binds to them |
+| `VerticalCameraLayout.cs` | **TASK 57 (the "vv" feature):** the vertical (9:16) tier's camera rules as pure math — `TileWidth`/`TileHeight` (270×152 master px = 480×270 in the 1080×1920 output), `Inset` (32 master px from the band's outer edge), `IsVerticalTier(QualityOption)` (portrait tier), `AreaFor(band, bottom)` (the band splits into two 607×540 areas), `MaxSizeFor(band)`, `SpotFor(band, w, h, centreX, centreY)` (the six spots — the area and column the tile's **centre** falls in, inset, never outside the band) and `DefaultSpot` (bottom-right, the corner the 16:9 default webcam uses), `FillsArea(band, width)` (the camera is wide enough to fill a whole area = "enlarged") and `SizeFor(band, requestedWidth)` (the Chat camera's TWO sizes - the small tile or one whole 607×540 area — whichever is nearer the requested width, so the resize handle has two detents) |
+| `ZoomSceneElement.cs` | **Transient zoom box (TASK 52, creator-corrected 2026-10-08):** carries the box rect AND the anchored `CaptureX`/`CaptureY` (the fixed box/2 capture window set on `ActivateZoom`; moving the box never touches it). `IsZoomActive` flips `Kind` Static→Dynamic (leaves the baked base while active); never persisted (LayoutStore save skips non-Source/non-WebcamSceneConfig rows), never shown in the layers list or the element template (`IsZoomLayer` gates both). The compositor SKIPS the active element in every layer loop and draws its 2x content LAST (layer n+1) via `ZoomMagnifier`. |
 | `Webcam.cs` | Singleton webcam identity: `Id`, `DeviceId`, `Name` (one row app-wide) |
-| `WebcamSceneConfig.cs` | Per-scene webcam placement (subclass of `SceneElement`): geometry + `IsVisible` + border (`BorderColor`/`BorderOpacity`/`BorderWidth`/`BorderAnimation`) + `VideoImageSource`; `WebcamId` links to `Webcam` |
+| `BackgroundEffect.cs` | **TASK 51:** per-webcam background effect enum `None` / `Remove` / `Blur`, carried by `WebcamSceneConfig` |
+| `BorderColorPalette.cs` | **TASK 60:** the colours the webcam's border-colour drop-down offers — `NamedColor(Hex, Name)` + `BorderColorPalette.All` (the single source of truth; the drop-down is bound to it) and `NameOf(hex)` (case-insensitive; **empty** for a colour outside the palette — "no name" is the honest answer, TASK 62). The creator asked for a colour NAME next to each hex: `#e94560  Crimson`. **TASK 63:** `EntryFor(hex)` (the palette entry for a hex, case-insensitively; a nameless entry for a colour outside the palette) and `OptionsFor(hex)` (the palette + that entry) — the two the drop-down binds to; `NamedColor.ToString()` is `"Crimson (#e94560)"` |
+| `WebcamSceneConfig.cs` | Per-scene webcam placement (subclass of `SceneElement`): geometry + `IsVisible` + border (`BorderColor`/`BorderOpacity`/`BorderWidth`/`BorderAnimation`) + `VideoImageSource`; `WebcamId` links to `Webcam`; **TASK 51:** `BackgroundEffect` + `BackgroundStrength` (0..1, default 0.5) + the radio-pill surface `RemoveBackground`/`BlurBackground` (one on turns the other off; both off = None) + `HasBackgroundEffect` (shows the strength slider); **TASK 57 (the "vv" feature):** the vertical (9:16) tier's OWN placement per scene — `VerticalX/Y/Width/Height/VerticalClipShape/VerticalRectWidth/VerticalRectHeight` (persisted, NULL = no vertical placement yet) + the transient `VerticalBand`/`VerticalLayoutLive`/`LandscapeX…LandscapeRectHeight` (the parked 16:9 layout) + `BeginVerticalLayout`/`EndVerticalLayout`/`CommitLiveLayoutToVertical` (the tier swap) and the `X`/`Y`/`Width`/`Height` overrides that clamp every write into the band; `VerticalShapeLocked` (the Chat scene's vertical layout is rect-only) **overrides** `ClipShape` + `ToggleClipShape()` so no writer can slip a circle in |
 | `QualityOption.cs` | Resolution tier record `(Display, Fps, Bitrate, Width, Height)`; `Label` formats as `1080p60 (8Mbps)` — drives the bottom-bar dropdown and the output-rect math |
 | `StreamConfig.cs` | `StreamConfig` (note: `TargetBitrate`/`Resolution` defaults are stale — not yet wired to the dropdown), `StreamHealth` (bitrate/FPS/dropped/duration), `StreamStatus` enum |
 | `MicStatus.cs` | Footer mic indicator: `NotConnected` / `Connected` / `Problem` — the state behind the MIC button's status dot (red = no device/capture off, green = capturing, yellow = a requested mic failed: in use/unplugged) |
-| `YouTube.cs` | `YouTubeChannel` and `ChatMessage` (chat feed) |
+| `YouTube.cs` | `YouTubeChannel` and `ChatMessage` (chat feed) — since TASK 43 every message carries `Kind` (`ChatEventKind` None/SuperChat/SuperSticker/NewMember/MemberGift/GiftReceived/MemberMilestone) + event payload fields (`SuperChatDisplayString`, `SuperStickerDescription`, `GiftNewMembersCount`, `GifterName`, `MilestoneMonths`) |
 | `Socials.cs` | **Social bar** (global layer, never a Source): `SocialService` enum (YouTube/Twitch/X/Instagram/TikTok/Facebook/Discord/Kick/Threads/Bluesky/GitHub/LinkedIn/Pinterest/Snapchat/Reddit/WhatsApp/Telegram/Link/Website/**Fediverse**), `SocialEntry` (Service/Handle/ProfileUrl/`FediverseSoftware`), `SocialsConfig` (Entries + `BarPosition` Top/Bottom + `BarEnabled` on/off — `BarJustify` dropped, column back-compat), `SocialServiceIcons` (canonical URL builder + `DetectService` (URL domain / fediverse `@user@domain` → **Fediverse** / bare→Website) + bundled SVG logo path data per service (`LogoDataFor`) + `LogoDataForFediverse(software)` mapping nodeinfo software names (mastodon/peertube/pixelfed/misskey/lemmy/pleroma/firefish) to logos with a generic fediverse glyph fallback (`FediverseIconData`) + `LockedIconData`/`DoNotIconData` — initials/colors gone) |
 
 Related: [`ViewModels/index.md`](../ViewModels/index.md) consume these;

Packaging/Package.appxmanifest

@@ -0,0 +1,78 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  LlamaCasty — Microsoft Store MSIX manifest (TASK 48).
+
+  Full trust is the whole point of this file: the app records to the user's profile,
+  launches the bundled ffmpeg as a CHILD PROCESS, opens an ordinary Win32 folder picker,
+  and drives WebView2. None of that works in an AppContainer, so this is a
+  packagedClassicApp at mediumIL with the runFullTrust restricted capability.
+
+  ⛔ Do NOT change this to appContainer: recording silently starts writing to a
+  per-package virtualised folder and the output "vanishes" (TASK 48 item 6).
+
+  ⚠️ Before submission, replace Publisher with the exact Publisher value Partner Center
+  shows for the account, and PublisherDisplayName with its display name — a mismatch is
+  a certification rejection. The version is bumped per submission.
+-->
+<Package
+    xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10"
+    xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10"
+    xmlns:uap10="http://schemas.microsoft.com/appx/manifest/uap/windows10/10"
+    xmlns:rescap="http://schemas.microsoft.com/appx/manifest/foundation/windows10/restrictedcapabilities"
+    IgnorableNamespaces="uap uap10 rescap">
+
+  <Identity
+      Name="LlamaCasty"
+      Publisher="CN=LlamaCasty"
+      Version="1.0.0.0"
+      ProcessorArchitecture="x64" />
+
+  <Properties>
+    <DisplayName>LlamaCasty</DisplayName>
+    <PublisherDisplayName>LlamaCasty</PublisherDisplayName>
+    <Description>Live streaming to YouTube: scenes, sources, a webcam with background effects, alerts, chat and recording.</Description>
+    <Logo>Assets\StoreLogo.png</Logo>
+  </Properties>
+
+  <Dependencies>
+    <TargetDeviceFamily
+        Name="Windows.Desktop"
+        MinVersion="10.0.19041.0"
+        MaxVersionTested="10.0.26100.0" />
+  </Dependencies>
+
+  <!-- English only (Store policy 10.7): a second language here means the listing
+       description must be localised into it too. -->
+  <Resources>
+    <Resource Language="en-US" />
+  </Resources>
+
+  <Applications>
+    <Application
+        Id="LlamaCasty"
+        Executable="ytLive.exe"
+        EntryPoint="Windows.FullTrustApplication"
+        uap10:TrustLevel="mediumIL"
+        uap10:RuntimeBehavior="packagedClassicApp">
+      <uap:VisualElements
+          DisplayName="LlamaCasty"
+          Description="Live streaming to YouTube: scenes, sources, a webcam with background effects, alerts, chat and recording."
+          BackgroundColor="#171928"
+          Square150x150Logo="Assets\Square150x150Logo.png"
+          Square44x44Logo="Assets\Square44x44Logo.png">
+        <!-- The wide and 310 tiles live on DefaultTile, not on VisualElements — the
+             Windows 10 uap:VisualElements schema has no such attributes. -->
+        <uap:DefaultTile
+            Wide310x150Logo="Assets\Wide310x150Logo.png"
+            Square310x310Logo="Assets\Square310x310Logo.png" />
+      </uap:VisualElements>
+    </Application>
+  </Applications>
+
+  <Capabilities>
+    <rescap:Capability Name="runFullTrust" />
+    <DeviceCapability Name="webcam" />
+    <DeviceCapability Name="microphone" />
+  </Capabilities>
+
+</Package>

README.md

@@ -1,63 +1,134 @@
-# ytLlive
+# LlamaCasty
 
 <p align="center">
   <img src="Assets/llamacasty-logo.jpg" alt="LlamaCasty — livestream smarter" height="120"/>
 </p>
 
-A creator-proof live-streaming and recording app for YouTube — native Windows (C# / WPF / .NET 8).
+A free, open-source Windows app for streaming live to YouTube and recording to your PC.
+Native Windows (C# / WPF / .NET 8). Website: https://llamacasty.com
 
-## Screenshot
+![LlamaCasty — main window with scenes, sources, and live preview](docs/ytLlive-preview.jpg)
 
-![ytLlive — main window with scenes, sources, and live preview](docs/ytLlive-preview.jpg)
+## Why I built it
 
-## Design Principle
+I'm Gramps. I've been gaming since 1981, and these days I stream *The Division 2* on YouTube.
 
-> This software is so intuitive that even the most right-brained person can easily intuit and use it.
+When I started streaming, I did what everybody does: I installed the big, general-purpose
+streaming tools. They're excellent software — powerful, flexible, and built to handle every
+platform, every camera rig, and every plugin anyone has ever dreamed up. That breadth is exactly
+what makes them great, and it's also what makes them a lot to learn. Before my first stream I was
+reading setup guides, picking encoders, balancing audio by hand, and wiring up scenes from
+scratch. The tools were ready for anything. I just wanted to go live.
 
-Every feature is measured against this. One-click go-live, sane YouTube defaults, visual scene
-building, and no dead ends — every action has a visible outcome.
+Most streamers I talk to are in the same spot. They don't need a tool for every platform and every
+setup — they need one that's ready for *theirs*. So I built LlamaCasty around three choices:
 
-## Why ytLlive
+- **One platform, done properly.** LlamaCasty streams to YouTube and only YouTube. That focus lets
+  it be built around how YouTube Live actually works — your channel, your chat, Super Chats and
+  memberships, Shorts-style vertical video, and the YouTube Partner Program — instead of treating
+  YouTube as one destination among many.
+- **Ready the moment you open it.** Five scenes (Starting, Live, BRB, Chat, Ending) are set up,
+  your game and voice are balanced with auto-ducking and voice polish built in, and YouTube's
+  settings are filled in. You arrange things by dragging them, then press Go Live.
+- **Calm while you're live.** A private Test Stream to practice, a layout that locks while you're
+  on air, and warnings only when YouTube reports a real problem.
 
-OBS treats YouTube as an afterthought; SLOBS is Twitch-first with YouTube bolted on. ytLlive is
-designed and dedicated to YouTube livestreaming and recording, and to YouTube's specific quirks.
+The general-purpose tools are the right choice when you need everything. LlamaCasty is for when you
+just want to get your show on air.
 
-## Account Assumption
+## Free, and staying that way
 
-ytLlive assumes you already have a YouTube creator account — connecting uses "Sign in with Google"
-to link that existing account. **ytLlive does not create accounts.** If you don't have a YouTube
-channel yet, set one up on YouTube first, then connect it here.
+LlamaCasty is free forever: no watermark, no branding on your stream, no subscription, no
+LlamaCasty account. It's also open source (see [License](#license)) — enjoy it, explore it,
+experiment with it. If it earns a spot in your setup and you'd like to say thanks, there's a
+coffee jar and a merch store linked from https://llamacasty.com. Completely optional, never
+expected, and the app will never ask.
 
-## Run
+## How it's built
 
-```bash
-dotnet build   # Windows only — WPF
-dotnet run
-```
+LlamaCasty is built through AI-assisted pair programming, under the direction of a developer with
+decades of experience. Architecture, product direction, and quality gates are human-owned; AI
+speeds up the implementation. The repo's memory map (below) is how that collaboration stays honest
+from one session to the next.
 
-## Version Roadmap
+## Requirements
 
-| Version | Scope |
-|---------|-------|
-| v0.1     | Scene/source management, YouTube RTMP ingest, YouTube OAuth2, live chat, stream health |
-| v0.2     | Recording to local file |
-| v0.3     | Stream scheduling |
-| v0.4     | Multi-destination restreaming |
-| 1.0      | General availability |
+- **64-bit Windows 10 or 11.** (The bundled FFmpeg and ONNX Runtime are 64-bit only.)
+- **A YouTube channel, to stream.** LlamaCasty links an existing channel with "Sign in with
+  Google" — it doesn't create accounts. Recording to an .mp4 works without signing in.
+- **Working sound in Windows.** Desktop and game audio come from your default output
+  automatically; you choose your mic in the app. LlamaCasty doesn't diagnose or repair Windows
+  audio — if it doesn't sound right in Windows, fix it there first.
+
+## Build from source
+
+The internal project, assembly, and namespace names are still `ytLive` (the app was renamed to
+LlamaCasty; the internals weren't). Building needs Windows and the .NET 8 SDK.
+
+1. **Fetch the bundled FFmpeg** (not in git — ~135 MB, pinned and SHA-256-verified):
+   `scripts/fetch-ffmpeg.sh`
+2. **Add your own Google OAuth client.** `Helpers/OAuthCredentials.cs` is gitignored. Create a
+   "Desktop app" OAuth client with the YouTube Data API v3 enabled in Google Cloud Console, then:
+
+   ```csharp
+   namespace ytLive.Helpers;
+
+   public static class OAuthCredentials
+   {
+       public const string ClientId = "your-client-id.apps.googleusercontent.com";
+       public const string ClientSecret = "your-client-secret";
+   }
+   ```
+3. **Build and run:**
+
+   ```bash
+   dotnet build ytLive.csproj
+   dotnet run --project ytLive.csproj
+   ```
+
+## Version roadmap
+
+**v1 is the finished product** (no v1.x releases are planned). Everything still in the queue lands
+in v1; anything not on the feature list is on the **"Out of product — permanently"** list in
+`TASKS.md` — read that before asking for a feature.
+
+What v1 ships: the five-scene control surface, webcam + screen capture, media + web + text
+sources, chat on stream, the social bar, mic/desktop audio with auto-ducking and TRAX background
+music, local recording, quality tiers including vertical 9:16, one-click go-live + scheduling,
+stream resilience, monetization awareness (YPP tracker), animated alerts, and webcam background
+removal and blur — all free and ungated.
 
 ## Structure
 
 | Path | Role |
 |------|------|
-| `Models/` | Scene, Source, QualityOption, StreamConfig, StreamHealth, YouTube channel/chat, Socials (social bar) |
-| `ViewModels/` | MainViewModel — scenes, stream controls, chat; GoLiveViewModel, ReuseImageViewModel, SocialsDialogViewModel |
-| `Services/` | YouTubeAuthService (OAuth2), YouTubeStreamService (broadcast/health), YouTubeChatService (chat polling), LayoutStore (SQLite), SocialValidator (social link/fediverse validation + nodeinfo icon resolution) |
-| `Helpers/` | ViewModelBase, RelayCommand, ImageCache, AppLog, FocusPreservingListBox, OAuthCredentials |
+| `Models/` | Scene, Source, WebcamSceneConfig, SceneElement, SceneCatalog, QualityOption, StreamConfig/Health, chat, Socials, BroadcastMetadata, Music, MicStatus, BackgroundEffect |
+| `ViewModels/` | MainViewModel (partial classes per area) + dialogs: GoLive, CameraPicker, MicPicker, HotkeyConfig, Socials, LiveBroadcastForm |
+| `Services/` | YouTube (OAuth, streams/broadcasts, chat polling), LayoutStore (SQLite), capture (camera/screen-capture/media-file via FFmpeg), SceneCompositor + FramePump, FFmpeg encoder + RTMP, audio pipeline (WASAPI loopback + mic, mixer, filters, ducker, limiter, TRAX), background effects (ONNX person segmentation), SocialValidator, notifications, hotkeys, SceneGraph, ChatOverlayLayer |
+| `Helpers/` | ViewModelBase, RelayCommand, ImageCache, AppLog, TokenStore (DPAPI), OAuthCredentials (gitignored), converters |
 | `Themes/` | `Controls.xaml` — the dark-theme control styles, merged once in `App.xaml` |
-| `MainWindow.xaml` | Dark-theme main UI: scene/source panel, preview, chat, status bar |
-| `SocialsDialog.xaml` | Social Media Site Promotion dialog — 6-slot social bar editor with sign-in gate and validation |
+| `MainWindow.xaml` | Dark-theme control surface: thumbnails + central preview, two-state left panel (layers/properties ↔ live chat), top bar, footer |
+| `tools/` | Offline helper tools (e.g. `selfie-seg/` — converts and verifies the background-effects model) |
 
 ## Docs (memory map)
 
-`schema.md` defines the conventions; `ai.md` is the AI/session guide;
-`TASKS.md` is the task queue. Each code directory carries an `index.md`.
+`schema.md` defines the conventions; `ai.md` is the AI/session guide; `TASKS.md` is the task
+queue; `HANDOFF.md` is the current state. Each code directory carries an `index.md`.
+
+## License
+
+LlamaCasty is free software, released under the **GNU General Public License v3.0 or later**
+([`LICENSE`](LICENSE)) with three additional terms permitted by GPL-3.0 section 7
+([`ADDITIONAL-TERMS.md`](ADDITIONAL-TERMS.md)):
+
+- **Keep the credit** — any copy, modified or not, shows "Based on LlamaCasty by Gramps —
+  https://llamacasty.com" in its About screen.
+- **Rename your fork** — modified versions are marked as modified and use a different name.
+- **No trademark rights** — the LlamaCasty name and llama logo aren't licensed. The icon and logo
+  files are all rights reserved and aren't covered by the GPL.
+
+The scene backgrounds and default alert video are AI-generated placeholders, licensed with the
+code — replace them with your own. Bundled third-party components keep their own licenses: see
+[`THIRD-PARTY-NOTICES.txt`](THIRD-PARTY-NOTICES.txt).
+
+Source code: https://llgit.llamachile.tube/gramps/LlamaCasty

RenameRecordingDialog.xaml

@@ -1,8 +1,8 @@
 <Window x:Class="ytLive.RenameRecordingDialog"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-        Title="Rename Recording" Height="230" Width="460"
-        Icon="/Assets/llamacasty-icon.png"
+        Title="Rename Recording" Height="304" Width="460"
+        Icon="/ytLive;component/Assets/llamacasty-icon.png"
         WindowStartupLocation="CenterOwner" ResizeMode="NoResize"
         ShowInTaskbar="False" Background="#1a1a2e">
 
@@ -32,7 +32,7 @@
                     Margin="0,20,0,0">
             <Button Content="Cancel" Click="Cancel_Click"
                     Style="{StaticResource YtButtonSecondary}" Margin="0,0,8,0"/>
-            <Button Content="Save" Click="Save_Click" Style="{StaticResource YtButton}" MinWidth="90"/>
+            <Button Content="Save" Click="Save_Click" Style="{StaticResource YtButton}" MinWidth="90" x:Name="SaveRecordingButton"/>
         </StackPanel>
     </Grid>
 </Window>

RenameRecordingDialog.xaml.cs

@@ -6,12 +6,16 @@ namespace ytLive;
 
 /// <summary>Modal that lets the creator rename an auto-named recording before it is
 /// finalized. Returns the chosen file stem (no extension) via <see cref="ResultFileName"/>,
-/// or <c>null</c> on Cancel / keep-auto-name.</summary>
+/// or <c>null</c> when the creator cleared the box and hit Save (keep the auto name).
+/// <para><c>DialogResult == false</c> means DISCARD — the caller deletes the footage
+/// rather than saving it (CREATOR RULING 2026-09-26). Enter on the pre-filled default
+/// is a Save.</para></summary>
 public partial class RenameRecordingDialog : Window
 {
     private readonly string _autoStem;
 
-    /// <summary>Stem (no extension) the creator chose, or <c>null</c> to keep auto-name.</summary>
+    /// <summary>Stem (no extension) the creator chose, or <c>null</c> when the box was
+    /// cleared on an explicit Save. Never set on Cancel.</summary>
     public string? ResultFileName { get; private set; }
 
     public RenameRecordingDialog(string autoStem)

Services/AlertClipDecoder.cs

@@ -0,0 +1,227 @@
+using System.Diagnostics;
+using System.IO;
+using ytLive.Helpers;
+using ytLive.Services.Audio;
+using ytLive.Services.Encoder;
+
+namespace ytLive.Services;
+
+/// <summary>
+/// TASK 47: one alert clip's playback — video frames + on-stream audio from the
+/// same file, both paced to real time. The alert box owns a decoder per event
+/// (start at play, dispose at drain) — unlike MediaSource's app-wide refcounted
+/// session, an alert REPLAYS the same clip each event, so a fresh decode per
+/// play is required. Video is rawvideo BGRA scaled to the box rect (the
+/// <see cref="MediaVideoSource"/> shape); audio is ffmpeg <c>f32le</c> at the
+/// mixer's native 48 kHz stereo (so the mixer ring needs no resampler). The
+/// fade is applied by the alert layer, not here.
+/// </summary>
+public interface IAlertClipDecoder : IDisposable
+{
+    /// <summary>Starts the decode loop (video + audio); raises the events off the
+    /// calling thread. Paced to real time so playback matches wall clock.</summary>
+    void Start();
+
+    /// <summary>Stops and kills any running decode subprocesses.</summary>
+    void Stop();
+
+    /// <summary>One decoded video frame (box-sized, straight-alpha BGRA).</summary>
+    event Action<VideoFrame>? FrameAvailable;
+
+    /// <summary>One chunk of on-stream audio (48 kHz stereo float).</summary>
+    event Action<AudioSample>? AudioReady;
+
+    /// <summary>Raised once when both streams have fully played out.</summary>
+    event Action? Completed;
+}
+
+/// <summary>Default <see cref="IAlertClipDecoder"/>: two ffmpeg subprocesses on
+/// the same file. Video via <see cref="RawVideoFrameReader"/> on a <c>rawvideo
+/// bgra</c> pipe (-an), audio via an <c>f32le -ac 2 -ar 48000</c> pipe (-vn).
+/// The seams (locator, process factory, frame-rate probe, delay) let tests drive
+/// a fake decoder without a real codec or Windows.</summary>
+public sealed class AlertClipDecoder : IAlertClipDecoder
+{
+    public event Action<VideoFrame>? FrameAvailable;
+    public event Action<AudioSample>? AudioReady;
+    public event Action? Completed;
+
+    private const int AudioSampleRate = 48000;
+    private const int AudioChannels = 2;
+    private const int AudioChunkFloats = 4800; // 50ms of stereo
+
+    private readonly string _path;
+    private readonly int _width;
+    private readonly int _height;
+    private readonly IFfmpegLocator _locator;
+    private readonly Func<IDecodeProcess> _processFactory;
+    private readonly IFrameRateProbe? _probe;
+    private readonly Func<TimeSpan, CancellationToken, Task> _delay;
+    private readonly CancellationTokenSource _cts = new();
+    private Task? _run;
+
+    public AlertClipDecoder(
+        string path,
+        int width,
+        int height,
+        IFfmpegLocator locator,
+        Func<IDecodeProcess> processFactory,
+        IFrameRateProbe? frameRateProbe = null,
+        Func<TimeSpan, CancellationToken, Task>? delay = null)
+    {
+        _path = path;
+        _width = width;
+        _height = height;
+        _locator = locator;
+        _processFactory = processFactory;
+        _probe = frameRateProbe;
+        _delay = delay ?? ((t, ct) => Task.Delay(t, ct));
+    }
+
+    public void Start()
+    {
+        if (_run != null) return;
+        _run = Task.Run(RunAsync, CancellationToken.None);
+    }
+
+    public void Stop() => _cts.Cancel();
+
+    public void Dispose()
+    {
+        _cts.Cancel();
+        _cts.Dispose();
+    }
+
+    private async Task RunAsync()
+    {
+        var ct = _cts.Token;
+        var videoFrames = 0;
+        var audioChunks = 0;
+        var failed = false;
+        try
+        {
+            double? frameRate = null;
+            if (_probe != null)
+                frameRate = await _probe.ProbeAsync(_path, ct).ConfigureAwait(false);
+            var frameDuration = frameRate is > 0 ? TimeSpan.FromSeconds(1.0 / frameRate.Value) : TimeSpan.Zero;
+
+            var ffmpegPath = await _locator.LocateAsync(ct).ConfigureAwait(false);
+
+            var videoTask = RunVideoAsync(ffmpegPath, frameDuration, ct);
+            var audioTask = RunAudioAsync(ffmpegPath, ct);
+            videoFrames = await videoTask.ConfigureAwait(false);
+            audioChunks = await audioTask.ConfigureAwait(false);
+        }
+        catch (OperationCanceledException)
+        {
+            failed = true;
+            return;
+        }
+        catch (Exception ex)
+        {
+            // A failed decode is not fatal: the alert layer falls back to the six
+            // animations (or the frame it already holds) exactly as a missing file.
+            // Logged so a silent blank box traces back to a decode failure.
+            failed = true;
+            AppLog.Write(ex, $"Alert clip decode failed ({Path.GetFileName(_path)})");
+        }
+
+        if (!ct.IsCancellationRequested)
+        {
+            AppLog.Write($"Alert clip end: {Path.GetFileName(_path)} frames={videoFrames} audioChunks={audioChunks} failed={failed}");
+            Completed?.Invoke();
+        }
+    }
+
+    private async Task<int> RunVideoAsync(string ffmpegPath, TimeSpan frameDuration, CancellationToken ct)
+    {
+        var args =
+            $"-hide_banner -loglevel error -i \"{_path}\" " +
+            $"-f rawvideo -pix_fmt bgra -vf scale={_width}:{_height} -an -";
+        using var process = _processFactory();
+        process.Start(new ProcessStartInfo
+        {
+            FileName = ffmpegPath,
+            Arguments = args,
+            UseShellExecute = false,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            CreateNoWindow = true,
+        });
+
+        var reader = new RawVideoFrameReader(_width, _height);
+        var buffer = new byte[65536];
+        var stream = process.StandardOutput;
+        var frames = 0;
+        while (!ct.IsCancellationRequested && !process.HasExited)
+        {
+            var read = await stream.ReadAsync(buffer, 0, buffer.Length, ct).ConfigureAwait(false);
+            if (read <= 0) break;
+            var chunk = new byte[read];
+            Buffer.BlockCopy(buffer, 0, chunk, 0, read);
+            foreach (var frame in reader.Feed(chunk))
+            {
+                frames++;
+                FrameAvailable?.Invoke(frame);
+                if (frameDuration > TimeSpan.Zero)
+                    await _delay(frameDuration, ct).ConfigureAwait(false);
+            }
+        }
+        return frames;
+    }
+
+    private async Task<int> RunAudioAsync(string ffmpegPath, CancellationToken ct)
+    {
+        var args =
+            $"-hide_banner -loglevel error -i \"{_path}\" " +
+            $"-f f32le -ac {AudioChannels} -ar {AudioSampleRate} -vn -";
+        using var process = _processFactory();
+        process.Start(new ProcessStartInfo
+        {
+            FileName = ffmpegPath,
+            Arguments = args,
+            UseShellExecute = false,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            CreateNoWindow = true,
+        });
+
+        var stream = process.StandardOutput;
+        var raw = new byte[65536];
+        var carry = new byte[0];
+        var floatScratch = new float[AudioChunkFloats];
+        var floatIndex = 0;
+        var chunks = 0;
+        // The pipe is byte-delimited only: a read may split a float, so leftover
+        // bytes are carried into the next read instead of dropped (a dropped
+        // half-float would desync the entire stream).
+        while (!ct.IsCancellationRequested && !process.HasExited)
+        {
+            var read = await stream.ReadAsync(raw, 0, raw.Length, ct).ConfigureAwait(false);
+            if (read <= 0) break;
+            var total = carry.Length + read;
+            var bytes = total <= raw.Length ? raw : new byte[total];
+            if (carry.Length > 0)
+            {
+                Buffer.BlockCopy(carry, 0, bytes, 0, carry.Length);
+                Buffer.BlockCopy(raw, 0, bytes, carry.Length, read);
+            }
+            var floatsTo = total - (total % 4);
+            for (var i = 0; i < floatsTo && floatIndex < floatScratch.Length; i += 4)
+                floatScratch[floatIndex++] = BitConverter.ToSingle(bytes, i);
+            carry = total > floatsTo ? bytes[floatsTo..total] : new byte[0];
+
+            while (floatIndex == floatScratch.Length)
+            {
+                chunks++;
+                AudioReady?.Invoke(new AudioSample(floatScratch, AudioSampleRate, AudioChannels));
+                // Pace the NEXT chunk so the whole clip's audio lands at real-time
+                // cadence (the fade in the alert layer tracks the same wall clock).
+                await _delay(TimeSpan.FromSeconds(AudioChunkFloats / (double)(AudioSampleRate * AudioChannels)), ct).ConfigureAwait(false);
+                floatScratch = new float[AudioChunkFloats];
+                floatIndex = 0;
+            }
+        }
+        return chunks;
+    }
+}

Services/AlertOverlayLayer.cs

@@ -0,0 +1,541 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Threading;
+using ytLive.Helpers;
+using ytLive.Models;
+using ytLive.Services.Audio;
+using ytLive.Services.Compositor;
+
+namespace ytLive.Services;
+
+/// <summary>
+/// The native alert box (OBS-style celebration zone, no third party). Owns the
+/// event queue and the animation clock: <see cref="ChatEventKind"/> events from
+/// the chat feed are enqueued one-at-a-time and played through a celebration
+/// animation (<see cref="AlertRenderer"/>) OR — when the alert-box video is
+/// configured and resolves — through a decoded clip. Frames are served to the
+/// stream compositor via <see cref="RenderFrame"/> and mirrored to the preview
+/// via <see cref="UpdatePreview"/>. Idle = transparent (null frame); playback is
+/// advanced by a 33ms dispatch ticker. The clock is exposed as
+/// <see cref="Advance"/> so tests drive playback deterministically without the
+/// timer. Ordinary chat rows (<see cref="ChatEventKind.None"/>) never enqueue —
+/// a subscriber mention is a chat row, not an alert.
+///
+/// TASK 47 (Stream Alerts video): a video-backed alert replaces the animation
+/// while a clip decodes (<see cref="IAlertClipDecoder"/>, one per play). The
+/// clip plays at its own media pace; the layer applies a ~300ms fade-in/out
+/// alpha envelope to the frames AND the audio samples (freeze-frame fade-out on
+/// the tail), clips the alert to the clip length, and forwards the scaled audio
+/// to the mixer's alert ring via <paramref name="audioSink"/> (no duck). The
+/// per-source config (path/default/ticker/volume) is resolved through
+/// <paramref name="clipPathResolver"/>; the ticker strip is served via
+/// <see cref="AlertTickerFrame"/>.
+/// </summary>
+public sealed class AlertOverlayLayer : IDisposable
+{
+    /// <summary>The fade-in/out ramp length (video alpha AND audio gain). Measured
+    /// against a real clip in the AlertLayerVideoTests unit; keep the ramp short
+    /// enough to read as a "pop-in" on stream (see ai.md).</summary>
+    internal const double FadeDurationSeconds = 0.30;
+
+    /// <summary>How long an alert waits for the first decoded frame or audio slab
+    /// before treating the clip as unplayable and falling back to the animations
+    /// (a silent decoder must never blank the alert box).</summary>
+    internal const double NoFrameFallbackSeconds = 1.0;
+
+    private static readonly TimeSpan TickInterval = TimeSpan.FromMilliseconds(33);
+
+    private readonly AlertRenderer _renderer;
+    private readonly Func<string, int, int, IAlertClipDecoder>? _clipDecoderFactory;
+    private readonly Func<Source, string?>? _clipPathResolver;
+    private readonly Action<AudioSample>? _audioSink;
+    private readonly Action<VideoFrame?>? _tickerPreviewSink;
+    private readonly Queue<ChatMessage> _queue = new();
+    private readonly DispatcherTimer? _ticker;
+
+    private ChatMessage? _current;
+    private Source? _currentBox;
+    private IAlertClipDecoder? _clip;
+    private VideoFrame? _latestClipFrame;
+    private bool _clipEof;
+    private double _clipEofElapsed;
+    private int _clipWidth;
+    private int _clipHeight;
+    private bool _clipSawFrame;
+    private bool _clipAudioHeard;
+    private string? _tickerText;
+    private AlertDisplayMethod _tickerMethod = AlertDisplayMethod.TickerScroll;
+    private double _elapsed;
+    private IEnumerable<Scene>? _scenes;
+
+    private int _contentVersion;
+    private int _frameVersion = -1;
+    private string? _frameKey;
+    private VideoFrame? _cachedFrame;
+    private DateTime _lastPreviewLog = DateTime.MinValue;
+
+    public AlertOverlayLayer(
+        AlertRenderer renderer,
+        Func<string, int, int, IAlertClipDecoder>? clipDecoderFactory = null,
+        Func<Source, string?>? clipPathResolver = null,
+        Action<AudioSample>? audioSink = null,
+        Action<VideoFrame?>? tickerPreviewSink = null)
+    {
+        _renderer = renderer;
+        _clipDecoderFactory = clipDecoderFactory;
+        _clipPathResolver = clipPathResolver;
+        _audioSink = audioSink;
+        _tickerPreviewSink = tickerPreviewSink;
+        if (Application.Current != null)
+        {
+            _ticker = new DispatcherTimer { Interval = TickInterval };
+            _ticker.Tick += (_, _) =>
+            {
+                Advance(TickInterval.TotalSeconds);
+                RefreshAlertPreviews();
+            };
+        }
+    }
+
+    /// <summary>Production entry from the chat feed: enqueue one event. Messages
+    /// arrive on the chat poller thread, so this marshals to the UI thread (same
+    /// rule as <see cref="ChatOverlayLayer.OnMessageReceived"/>) — the preview
+    /// writes create WPF <see cref="WriteableBitmap"/> instances, and creating a
+    /// DependencySource off the UI thread crashes the WPF binding engine
+    /// (ArgumentException "Must create DependencySource on same Thread").</summary>
+    public void OnMessageReceived(ChatMessage message, IEnumerable<Scene> scenes)
+    {
+        var app = Application.Current;
+        if (app != null && !app.Dispatcher.CheckAccess())
+        {
+            app.Dispatcher.Invoke(() => Ingest(message, scenes));
+            return;
+        }
+        Ingest(message, scenes);
+    }
+
+    private void Ingest(ChatMessage message, IEnumerable<Scene> scenes)
+    {
+        _scenes = scenes;
+        Enqueue(message);
+        _ticker?.Start();
+        RefreshAlertPreviews();
+    }
+
+    /// <summary>Queue an event (pure — also the test seam). Chat rows carry
+    /// <see cref="ChatEventKind.None"/> and are ignored: no alert for a mention.</summary>
+    public void Enqueue(ChatMessage message)
+    {
+        if (message.Kind == ChatEventKind.None) return;
+        if (_queue.Count >= 10) return; // back-to-back floods drop the tail, never stall playback
+        _queue.Enqueue(message);
+        if (_current == null)
+        {
+            _current = _queue.Dequeue();
+            _elapsed = 0;
+            BeginClip();
+        }
+        _contentVersion++;
+    }
+
+    /// <summary>Advance the playback clock (the ticker's beat — and the test seam;
+    /// tests call this directly and never start the timer). Draining the queue to
+    /// nothing stops the ticker and leaves the box transparent.</summary>
+    public void Advance(double deltaSeconds)
+    {
+        // Video-backed alert: duration is clip-driven. The clip plays at media
+        // pace; once it EOFs the last frame sweeps through the fade-out before
+        // the alert moves on (a hard cut at EOF would pop, not fade).
+        if (_clip != null)
+        {
+            _elapsed += deltaSeconds;
+            // A decoder that starts but produces not a single frame (or slab of
+            // audio) is dead weight — the box would sit transparent for the whole
+            // alert. Give it a short grace, then fall back to the animations so an
+            // alert ALWAYS renders (the live decode failure at 2026-09-26 11:44 was
+            // this exact void, invisible in the log).
+            if (!_clipSawFrame && !_clipAudioHeard && _elapsed >= NoFrameFallbackSeconds)
+            {
+                System.Diagnostics.Debug.WriteLine("Alert clip yielded no frames in 1s — falling back to the animation");
+                StopClip();
+                _elapsed = 0;
+                _contentVersion++;
+                return;
+            }
+            if (_clipEof && _elapsed - _clipEofElapsed >= FadeDurationSeconds)
+            {
+                _clipEof = false;
+                StopClip();
+                _current = null;
+                _elapsed = 0;
+                AdvanceToNext();
+            }
+            _contentVersion++;
+            return;
+        }
+
+        if (_current == null)
+        {
+            if (_queue.Count == 0) return;
+            _current = _queue.Dequeue();
+            _elapsed = 0;
+            BeginClip();
+            _contentVersion++;
+            return;
+        }
+
+        _elapsed += deltaSeconds;
+        if (_elapsed >= DurationOf(_current))
+        {
+            _current = null;
+            _elapsed = 0;
+            AdvanceToNext();
+        }
+        _contentVersion++;
+    }
+
+    /// <summary>Whether an alert is currently playing or queued.</summary>
+    public bool IsPlaying => _current != null || _queue.Count > 0;
+
+    /// <summary>The live-output frame for one AlertBox element: the decoded clip
+    /// frame (faded) while a clip is active, else the animation frame, null
+    /// (transparent) when idle.</summary>
+    public VideoFrame? RenderFrame(Source alertBox)
+    {
+        if (_current == null)
+        {
+            _frameKey = null;
+            return null;
+        }
+
+        if (_clip != null)
+            return RenderClipFrame(alertBox);
+
+        var width = (int)Math.Max(1, alertBox.Width);
+        var height = (int)Math.Max(1, alertBox.Height);
+        var key = $"{width}x{height}|{_current.Id}|{Progress()}";
+
+        if (_frameKey == key && _frameVersion == _contentVersion)
+            return _cachedFrame;
+
+        var app = Application.Current;
+        if (app != null && !app.Dispatcher.CheckAccess())
+        {
+            var capturedKey = key;
+            var capturedVersion = _contentVersion;
+            return app.Dispatcher.Invoke(() =>
+            {
+                if (_frameKey == capturedKey && _frameVersion == capturedVersion)
+                    return _cachedFrame;
+                return RenderCore(alertBox, width, height, capturedKey, capturedVersion);
+            });
+        }
+
+        return RenderCore(alertBox, width, height, key, _contentVersion);
+    }
+
+    /// <summary>The ticker strip as the alert box shows it: a marquee, a pulse or a
+    /// static pill naming the event while an alert plays, else null. Pure byte-math
+    /// per call so the frame pump can read it on any thread (the text strip is
+    /// rasterized once on the UI thread and cached).
+    /// <para><b>Creator ruling 2026-09-26:</b> the strip is composited INSIDE the
+    /// Stream Alerts box, not as a full-width bar at the top edge of the frame — "the
+    /// ticker should appear over the stream alerts video, not over the entire preview
+    /// window". So the frame is rendered at the box's own size and carries the box's
+    /// origin on <see cref="VideoFrame.Placement"/>; every blit site reads
+    /// <see cref="VideoFrame.OriginX"/>/<see cref="VideoFrame.OriginY"/> instead of
+    /// a hardcoded 0. <b>No alert box in the scene means no ticker at all</b> — there
+    /// is no longer a global position for it to live in.</para></summary>
+    public VideoFrame? AlertTickerFrame
+    {
+        get
+        {
+            if (_current == null || string.IsNullOrWhiteSpace(_tickerText)) return null;
+            var box = _currentBox;
+            if (box == null) return null;
+
+            var w = (int)Math.Max(1, Math.Round(box.Width));
+            var h = (int)Math.Max(1, Math.Min(
+                Math.Round(box.Height), AlertTickerRenderer.Height));
+            var frame = AlertTickerRenderer.Render(
+                _tickerText!, _elapsed, _tickerMethod, AlertSeconds(),
+                TickerReadsPerAlert, w, h);
+            return frame == null
+                ? null
+                : new VideoFrame(frame.Width, frame.Height, frame.BgraPixels)
+                {
+                    Placement = ((int)Math.Round(box.X), (int)Math.Round(box.Y)),
+                };
+        }
+    }
+
+    /// <summary>How many times the marquee must cross the frame per alert, so the
+    /// announcement is actually readable inside a 10s clip (2026-09-26: the old
+    /// fixed 140px/s took ~17s per pass, so a 10s alert showed it barely once).</summary>
+    internal const int TickerReadsPerAlert = 3;
+
+    /// <summary>Assumed alert length for the marquee rhythm. The clip's real length
+    /// isn't known until it EOFs, and the shipped default clip is 10s — the number
+    /// the creator's "three reads" target is stated against.</summary>
+    internal const double AssumedAlertSeconds = 10.0;
+
+    private double AlertSeconds() => _clip != null ? AssumedAlertSeconds : DurationOf(_current!);
+
+
+    private VideoFrame? RenderClipFrame(Source alertBox)
+    {
+        var frame = _latestClipFrame;
+        if (frame == null) return null;
+
+        var w = (int)Math.Max(1, alertBox.Width);
+        var h = (int)Math.Max(1, alertBox.Height);
+        if (frame.Width != w || frame.Height != h)
+            frame = StretchMath.BilinearScale(frame, w, h);
+
+        var fade = FadeAt();
+        if (fade >= 1.0) return frame;
+
+        // Straight-alpha source-over on the compositor side: scale the source
+        // alpha by the envelope so the clip blends out (a 680x200 copy per fade
+        // tick is trivial; outside the ramps fade==1 returns the raw frame).
+        var copy = new byte[frame.BgraPixels.Length];
+        Buffer.BlockCopy(frame.BgraPixels, 0, copy, 0, copy.Length);
+        var a = (byte)(fade * 255 + 0.5);
+        for (var i = 3; i < copy.Length; i += 4)
+            copy[i] = (byte)((copy[i] * a) >> 8);
+        return new VideoFrame(frame.Width, frame.Height, copy);
+    }
+
+    private double FadeAt()
+    {
+        if (_clip == null) return 1.0;
+        if (_clipEof)
+            return Math.Clamp(1.0 - (_elapsed - _clipEofElapsed) / FadeDurationSeconds, 0.0, 1.0);
+        return Math.Clamp(_elapsed / FadeDurationSeconds, 0.0, 1.0);
+    }
+
+    private void BeginClip()
+    {
+        StopClip();
+        _tickerText = null;
+        if (_current == null) return;
+
+        var box = _scenes?.SelectMany(s => s.Elements).OfType<Source>()
+            .FirstOrDefault(s => s.Type == SourceType.AlertBox);
+        _currentBox = box;
+        if (box != null && box.AlertShowTicker)
+        {
+            _tickerText = ComposeTicker(_current);
+            _tickerMethod = box.AlertDisplayMethod;
+        }
+
+        if (box == null || _clipDecoderFactory == null) return;
+        var path = _clipPathResolver?.Invoke(box);
+        if (string.IsNullOrWhiteSpace(path)) return;
+
+        _clipWidth = (int)Math.Max(1, box.Width);
+        _clipHeight = (int)Math.Max(1, box.Height);
+        try
+        {
+            _clipSawFrame = false;
+            _clipAudioHeard = false;
+            _clip = _clipDecoderFactory(path, _clipWidth, _clipHeight);
+            _clip.FrameAvailable += OnClipFrame;
+            _clip.AudioReady += OnClipAudio;
+            _clip.Completed += OnClipCompleted;
+            _clip.Start();
+            AppLog.Write($"Alert clip start: box {box.Id} path '{path}' {_clipWidth}x{_clipHeight}");
+        }
+        catch (Exception ex)
+        {
+            AppLog.Write(ex, "Alert clip setup failed");
+            StopClip(); // decode setup failed (bad path) — fall back to animations
+        }
+    }
+
+    private void StopClip()
+    {
+        var clip = _clip;
+        _clip = null;
+        _latestClipFrame = null;
+        _clipEof = false;
+        _clipSawFrame = false;
+        _clipAudioHeard = false;
+        if (clip == null) return;
+        clip.FrameAvailable -= OnClipFrame;
+        clip.AudioReady -= OnClipAudio;
+        clip.Completed -= OnClipCompleted;
+        try { clip.Stop(); } catch { /* already stopped */ }
+        clip.Dispose();
+    }
+
+    private void OnClipFrame(VideoFrame frame)
+    {
+        _clipSawFrame = true;
+        _latestClipFrame = frame;
+    }
+
+    private void OnClipCompleted()
+    {
+        _clipEof = true;
+        _clipEofElapsed = _elapsed;
+    }
+
+    private void OnClipAudio(AudioSample sample)
+    {
+        if (_audioSink == null) return;
+        _clipAudioHeard = true;
+        var volume = (float)Math.Clamp(_currentBox?.AlertVideoVolume ?? 1.0, 0.0, 1.0);
+        if (volume <= 0f) return;
+        var fade = FadeAt();
+        if (fade <= 0.0) return;
+
+        var data = sample.Samples;
+        if (fade < 1.0 || Math.Abs(volume - 1f) > 0.001f)
+        {
+            data = new float[data.Length];
+            var gain = volume * (float)fade;
+            for (var i = 0; i < sample.Samples.Length; i++)
+                data[i] = sample.Samples[i] * gain;
+        }
+        _audioSink(new AudioSample(data, sample.SampleRate, sample.Channels));
+    }
+
+    private void AdvanceToNext()
+    {
+        if (_queue.Count > 0)
+        {
+            _current = _queue.Dequeue();
+            _elapsed = 0;
+            BeginClip();
+        }
+        else
+        {
+            _ticker?.Stop();
+        }
+    }
+
+    private VideoFrame? RenderCore(Source alertBox, int width, int height, string key, int version)
+    {
+        _frameKey = key;
+        _frameVersion = version;
+        if (_current == null) return _cachedFrame = null;
+        return _cachedFrame = _renderer.Render(_current, Progress(), width, height);
+    }
+
+    private double Progress()
+    {
+        if (_current == null) return 0;
+        return Math.Clamp(_elapsed / DurationOf(_current), 0.0, 1.0);
+    }
+
+    private static double DurationOf(ChatMessage m) => m.Kind switch
+    {
+        ChatEventKind.SuperChat => 4.6,
+        ChatEventKind.SuperSticker => 4.2,
+        ChatEventKind.NewMember => 4.0,
+        ChatEventKind.MemberGift => 5.0,
+        ChatEventKind.GiftReceived => 4.4,
+        ChatEventKind.MemberMilestone => 4.8,
+        _ => 4.0,
+    };
+
+    private static string ComposeTicker(ChatMessage m)
+    {
+        var label = m.Kind switch
+        {
+            ChatEventKind.SuperChat => "Super Chat",
+            ChatEventKind.SuperSticker => "Super Sticker",
+            ChatEventKind.NewMember => "New Member",
+            ChatEventKind.MemberGift => "Membership Gift",
+            ChatEventKind.GiftReceived => "Gifted Membership",
+            ChatEventKind.MemberMilestone => "Member Milestone",
+            _ => "Stream Alert",
+        };
+        var amount = m.Kind is ChatEventKind.SuperChat or ChatEventKind.SuperSticker
+            && m.SuperChatDisplayString is { Length: > 0 } s
+                ? $" · {s}"
+                : "";
+        return $"{m.AuthorName} — {label}{amount}";
+    }
+
+    /// <summary>Render the current state onto one AlertBox preview (mirrors chat):
+    /// the playing frame, or null when idle so the source shows nothing until an
+    /// event actually fires.</summary>
+    public void UpdatePreview(Source alertBox)
+    {
+        try
+        {
+            var frame = RenderFrame(alertBox);
+            // Preview eyes (TASK 47, 2026-09-26): a healthy decode painted nothing on
+            // the canvas. UpdatePreview swallows its failures to Debug, so say once a
+            // second whether the box is being handed a frame at all.
+            if (IsPlaying)
+            {
+                var now = DateTime.UtcNow;
+                if (now - _lastPreviewLog >= TimeSpan.FromSeconds(1))
+                {
+                    _lastPreviewLog = now;
+                    AppLog.Write($"Alert preview: box {alertBox.Id} frame="
+                        + (frame == null ? "null" : $"{frame.Width}x{frame.Height} a{frame.BgraPixels[3]}"));
+                }
+            }
+            if (frame == null)
+            {
+                alertBox.VideoImageSource = null;
+                return;
+            }
+            var width = (int)Math.Max(1, alertBox.Width);
+            var height = (int)Math.Max(1, alertBox.Height);
+            var bitmap = new WriteableBitmap(width, height, 96, 96, PixelFormats.Bgra32, null);
+            bitmap.WritePixels(new Int32Rect(0, 0, width, height), frame.BgraPixels, frame.Stride, 0);
+            alertBox.VideoImageSource = bitmap;
+        }
+        catch (Exception ex)
+        {
+            System.Diagnostics.Debug.WriteLine($"Alert preview failed: {ex.Message}");
+        }
+    }
+
+    /// <summary>Wire property-change subscriptions for all AlertBox sources across
+    /// every scene (geometry changes re-render), and clear/reset their previews.</summary>
+    public void UpdateConfiguredBoxes(IEnumerable<Scene> scenes)
+    {
+        _scenes = scenes;
+        foreach (var scene in scenes)
+        foreach (var alertBox in scene.Elements.OfType<Source>().Where(s => s.Type == SourceType.AlertBox))
+        {
+            alertBox.PropertyChanged += (_, e) =>
+            {
+                if (e.PropertyName is nameof(Source.Width) or nameof(Source.Height))
+                    UpdatePreview(alertBox);
+            };
+            UpdatePreview(alertBox);
+        }
+    }
+
+    private void RefreshAlertPreviews()
+    {
+        // The announcement strip is a GLOBAL 1920px overlay, not a per-box frame, so
+        // it gets its own sink: until this existed the strip went only to the frame
+        // pump and was therefore invisible in the preview pane the creator watches
+        // (2026-09-26 — "I do not see the scrolling text").
+        _tickerPreviewSink?.Invoke(AlertTickerFrame);
+
+        if (_scenes == null) return;
+        foreach (var alertBox in _scenes.SelectMany(s => s.Elements).OfType<Source>()
+                     .Where(s => s.Type == SourceType.AlertBox))
+            UpdatePreview(alertBox);
+    }
+
+    public void Dispose()
+    {
+        _ticker?.Stop();
+        _queue.Clear();
+        _current = null;
+        StopClip();
+    }
+}

Services/AlertRenderer.cs

@@ -0,0 +1,389 @@
+using System.Globalization;
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using ytLive.Models;
+
+namespace ytLive.Services;
+
+/// <summary>
+/// Renders one event's celebration animation into a BGRA8 frame for the AlertBox.
+/// Six event kinds, six UNIQUE animations — each a distinct gesture, palette and
+/// layout (the creator's ruling: these are the monetization shout-outs and free
+/// branded product placement; a one-template recoloring loses all interest in two
+/// iterations). Each card carries the bottom-right brand line so every broadcast
+/// of an event is an in-video ad placement.
+///
+/// <paramref name="t01"/> walks 0→1 over the whole animation; each kind splits it
+/// into enter / hold / exit phases with its own easing.
+/// </summary>
+public sealed class AlertRenderer
+{
+    private const double EnterEnd = 0.16;
+    private const double ExitStart = 0.80;
+    private const string Brand = "made with LlamaCasty!";
+
+    private static readonly CultureInfo Invariant = CultureInfo.InvariantCulture;
+    private static readonly Color White = Colors.White;
+    private static readonly Color[] ConfettiPalette =
+    {
+        Color.FromRgb(0xf4, 0x2f, 0x5f), Color.FromRgb(0xff, 0xd1, 0x66),
+        Color.FromRgb(0x38, 0xb6, 0xf8), Color.FromRgb(0xa7, 0x8b, 0xfa),
+        Color.FromRgb(0x39, 0xd3, 0x53),
+    };
+
+    public VideoFrame Render(ChatMessage e, double t01, int width, int height)
+    {
+        return e.Kind switch
+        {
+            ChatEventKind.SuperChat => SuperChat(e, t01, width, height),
+            ChatEventKind.SuperSticker => SuperSticker(e, t01, width, height),
+            ChatEventKind.NewMember => NewMember(e, t01, width, height),
+            ChatEventKind.MemberGift => MemberGift(e, t01, width, height),
+            ChatEventKind.GiftReceived => GiftReceived(e, t01, width, height),
+            ChatEventKind.MemberMilestone => Milestone(e, t01, width, height),
+            _ => SuperChat(e, t01, width, height),
+        };
+    }
+
+    private static VideoFrame SuperChat(ChatMessage e, double t, int w, int h)
+    {
+        var dpi = 96.0;
+        var visual = new DrawingVisual();
+        using (var ctx = visual.RenderOpen())
+        {
+            var margin = Math.Max(w, h) * 0.03;
+            var cardX = margin;
+            var cardW = w - margin * 2;
+            var cardH = h - margin * 2;
+            var cardCX = cardX + cardW / 2;
+
+            var enter = Clamp01(t / EnterEnd);
+            var exit = Clamp01((t - ExitStart) / (1 - ExitStart));
+            var exitEase = EaseInCubic(exit);
+            var cardY = Lerp(h + cardH, margin, EaseOutCubic(enter));
+            cardY = Lerp(cardY, -cardH, exitEase);
+
+            DrawCard(ctx, cardX, cardY, cardW, cardH, "#0d3b2b", "#14532d", 14);
+            DrawBrand(ctx, cardX, cardY, cardW, cardH);
+
+            var shownAmount = e.SuperChatDisplayString
+                ?? (e.SuperChatCurrency is { Length: > 0 } cur ? $"{cur}{e.SuperChatAmount:0.00}" : $"${e.SuperChatAmount:0.00}");
+            var fontSize = cardH * 0.24;
+            DrawCentered(ctx, shownAmount, cardCX, cardY + cardH * 0.24, fontSize, FontWeights.Bold, Color.FromRgb(0xff, 0xd1, 0x66), cardW);
+
+            DrawCentered(ctx, e.AuthorName, cardCX, cardY + cardH * 0.56, cardH * 0.13, FontWeights.SemiBold, White, cardW);
+            DrawCentered(ctx, e.Message, cardCX, cardY + cardH * 0.74, cardH * 0.10, FontWeights.Normal, Color.FromRgb(0xdd, 0xff, 0xf0), cardW * 0.92);
+
+            if (t >= EnterEnd && t <= ExitStart)
+            {
+                var sweep = (t - EnterEnd) / (ExitStart - EnterEnd);
+                var shineX = cardX + (sweep * 2 - 0.5) * cardW;
+                ctx.DrawRectangle(
+                    new LinearGradientBrush(
+                        Colors.Transparent,
+                        Color.FromArgb(0x30, 0xff, 0xff, 0xff),
+                        new Point(0, 0),
+                        new Point(1, 0)),
+                    null,
+                    new Rect(shineX - cardW * 0.25, cardY, cardW * 0.5, cardH));
+            }
+        }
+        return CreateFrame(visual, w, h, dpi);
+    }
+
+    private static VideoFrame SuperSticker(ChatMessage e, double t, int w, int h)
+    {
+        var dpi = 96.0;
+        var visual = new DrawingVisual();
+        using (var ctx = visual.RenderOpen())
+        {
+            var margin = Math.Max(w, h) * 0.04;
+            var cardW = w - margin * 2;
+            var cardH = h - margin * 2;
+            var cardCX = w / 2.0;
+
+            var enter = Clamp01(t / EnterEnd);
+            var exit = Clamp01((t - ExitStart) / (1 - ExitStart));
+            var scale = EaseOutBack(enter) * (0.85 + 0.15 * (1 - exit));
+            if (t > EnterEnd && t <= ExitStart)
+                scale = 1.0 + 0.02 * Math.Sin(t * 26.0);
+            var alpha = 1.0 - exit;
+
+            ctx.PushOpacity(alpha);
+
+            var slick = new RotateTransform(-6, w / 2.0, h / 2.0);
+            ctx.PushTransform(slick);
+            ctx.PushTransform(new ScaleTransform(scale, scale, w / 2.0, h / 2.0));
+
+            DrawCard(ctx, margin, margin, cardW, cardH, "#4a044e", "#7e22ce", 20);
+            DrawBrand(ctx, margin, margin, cardW, cardH);
+
+            var desc = string.IsNullOrWhiteSpace(e.SuperStickerDescription) ? "SUPER STICKER" : e.SuperStickerDescription.ToUpperInvariant();
+            DrawCentered(ctx, desc, cardCX, h / 2.0 - cardH * 0.12, cardH * 0.17, FontWeights.Bold, White, cardW * 0.9);
+
+            DrawCentered(ctx, e.AuthorName, cardCX, h / 2.0 + cardH * 0.16, cardH * 0.12, FontWeights.SemiBold, Color.FromRgb(0xff, 0xb3, 0xd9), cardW * 0.9);
+            var tier = e.SuperChatDisplayString ?? (e.SuperChatCurrency is { Length: > 0 } cur ? $"{cur}{e.SuperChatAmount:0.00}" : null);
+            if (!string.IsNullOrWhiteSpace(tier))
+                DrawCentered(ctx, tier, cardCX, h / 2.0 + cardH * 0.32, cardH * 0.10, FontWeights.Bold, Color.FromRgb(0xff, 0xd1, 0x66), cardW * 0.9);
+
+            ctx.Pop();
+            ctx.Pop();
+            ctx.Pop();
+        }
+        return CreateFrame(visual, w, h, dpi);
+    }
+
+    private static VideoFrame NewMember(ChatMessage e, double t, int w, int h)
+    {
+        var dpi = 96.0;
+        var visual = new DrawingVisual();
+        using (var ctx = visual.RenderOpen())
+        {
+            var margin = Math.Max(w, h) * 0.035;
+            var cardW = w - margin * 2;
+            var cardH = h - margin * 2;
+            var cardCX = w / 2.0;
+
+            var enter = Clamp01(t / EnterEnd);
+            var exit = Clamp01((t - ExitStart) / (1 - ExitStart));
+            var cardY = Lerp(-cardH, margin, EaseOutCubic(enter));
+            cardY = Lerp(cardY, h, EaseInCubic(exit));
+
+            DrawCard(ctx, margin, cardY, cardW, cardH, "#2e1065", "#5b21b6", 16);
+            DrawBrand(ctx, margin, cardY, cardW, cardH);
+
+            if (t <= ExitStart)
+            {
+                var bandP = EaseOutCubic(Clamp01(t / 0.22));
+                ctx.DrawRectangle(
+                    new LinearGradientBrush(Color.FromArgb(0, 0xff, 0xff, 0xff), Colors.Transparent, new Point(0, 0), new Point(0, 1)),
+                    null,
+                    new Rect(margin, cardY + cardH * 0.30, cardW * bandP, cardH * 0.18));
+            }
+
+            DrawCentered(ctx, e.AuthorName, cardCX, cardY + cardH * 0.36, cardH * 0.22, FontWeights.Bold, White, cardW * 0.9);
+            DrawCentered(ctx, "JOINED THE MEMBERSHIP", cardCX, cardY + cardH * 0.62, cardH * 0.11, FontWeights.SemiBold, Color.FromRgb(0xf5, 0xd0, 0xfe), cardW * 0.9);
+
+            var level = string.IsNullOrWhiteSpace(e.MembershipLevel) ? "MEMBER" : e.MembershipLevel.ToUpperInvariant();
+            DrawCentered(ctx, level, cardCX, cardY + cardH * 0.80, cardH * 0.10, FontWeights.Bold, Color.FromRgb(0xff, 0xd1, 0x66), cardW * 0.9);
+        }
+        return CreateFrame(visual, w, h, dpi);
+    }
+
+    private static VideoFrame MemberGift(ChatMessage e, double t, int w, int h)
+    {
+        var dpi = 96.0;
+        var visual = new DrawingVisual();
+        using (var ctx = visual.RenderOpen())
+        {
+            var margin = Math.Max(w, h) * 0.035;
+            var cardW = w - margin * 2;
+            var cardH = h - margin * 2;
+            var cardCX = w / 2.0;
+
+            var enter = Clamp01(t / EnterEnd);
+            var exit = Clamp01((t - ExitStart) / (1 - ExitStart));
+            var cardX = Lerp(-cardW, margin, EaseOutCubic(enter));
+            cardX = Lerp(cardX, -cardW, EaseInCubic(exit));
+
+            DrawCard(ctx, cardX, margin, cardW, cardH, "#422006", "#a16207", 16);
+            DrawBrand(ctx, cardX, margin, cardW, cardH);
+
+            var count = Math.Max(1, e.GiftNewMembersCount);
+            var spread = 1.0 - exit;
+            var hero = count > 1 ? $"×{count}" : "MEMBERSHIP";
+            DrawCentered(ctx, hero, cardCX, margin + cardH * 0.24, cardH * 0.26, FontWeights.Bold, Color.FromRgb(0xff, 0xd1, 0x66), cardW * 0.8);
+            DrawCentered(ctx, $"{e.AuthorName} is gifting", cardCX, margin + cardH * 0.52, cardH * 0.11, FontWeights.SemiBold, White, cardW * 0.9);
+
+            var chipCount = Math.Min(count, 6);
+            for (var i = 0; i < chipCount; i++)
+            {
+                var slot = (chipCount - 1) * 0.5;
+                var gap = cardH * 0.13 * EaseOutCubic(Clamp01(t / 0.30)) * spread;
+                var chipX = cardCX + (i - slot) * gap;
+                var chipY = margin + cardH * 0.70 + Math.Sin((i + t * 6) * 2.4) * cardH * 0.015;
+                ctx.DrawRoundedRectangle(
+                    new SolidColorBrush(Color.FromRgb(0xff, 0xf3, 0xc4)),
+                    null,
+                    new Rect(chipX - cardH * 0.05, chipY, cardH * 0.10, cardH * 0.10),
+                    cardH * 0.03, cardH * 0.03);
+            }
+        }
+        return CreateFrame(visual, w, h, dpi);
+    }
+
+    private static VideoFrame GiftReceived(ChatMessage e, double t, int w, int h)
+    {
+        var dpi = 96.0;
+        var visual = new DrawingVisual();
+        using (var ctx = visual.RenderOpen())
+        {
+            var margin = Math.Max(w, h) * 0.04;
+            var cardW = w - margin * 2;
+            var cardH = h - margin * 2;
+            var cardCX = w / 2.0;
+
+            var enter = Clamp01(t / (EnterEnd * 1.4));
+            var exit = Clamp01((t - ExitStart) / (1 - ExitStart));
+            var scale = 0.5 + 0.5 * EaseOutBack(enter);
+            var alpha = Math.Min(1.0, enter * 1.6) * (1 - exit);
+
+            ctx.PushOpacity(alpha);
+            ctx.PushTransform(new ScaleTransform(scale, scale, w / 2.0, h / 2.0));
+
+            DrawCard(ctx, margin, margin, cardW, cardH, "#14532d", "#4c1d95", 18);
+            DrawBrand(ctx, margin, margin, cardW, cardH);
+
+            // Confetti falling inside the card during the hold (deterministic seed).
+            if (t >= EnterEnd && t <= ExitStart)
+            {
+                var hold = (t - EnterEnd) / (ExitStart - EnterEnd);
+                for (var i = 0; i < 14; i++)
+                {
+                    var seed = i * 37 + 11;
+                    var dotX = margin + cardW * (((seed * 53) % 97) / 97.0);
+                    var dotY = margin + cardH * (((seed + hold * 0.85) % 1.0));
+                    var size = cardH * 0.02 + (i % 3) * cardH * 0.006;
+                    ctx.DrawRectangle(
+                        new SolidColorBrush(ConfettiPalette[i % ConfettiPalette.Length]),
+                        null,
+                        new Rect(dotX, dotY, size, size));
+                }
+            }
+
+            DrawCentered(ctx, "GIFTED MEMBERSHIP", cardCX, margin + cardH * 0.22, cardH * 0.12, FontWeights.Bold, Color.FromRgb(0xff, 0xd1, 0x66), cardW * 0.9);
+            var giver = string.IsNullOrWhiteSpace(e.GifterName) ? e.AuthorName : e.GifterName;
+            DrawCentered(ctx, giver, cardCX, margin + cardH * 0.42, cardH * 0.20, FontWeights.Bold, White, cardW * 0.9);
+            DrawCentered(ctx, "gave you a membership — celebrate!", cardCX, margin + cardH * 0.68, cardH * 0.11, FontWeights.Normal, Color.FromRgb(0xdb, 0xff, 0xf0), cardW * 0.9);
+
+            ctx.Pop();
+            ctx.Pop();
+        }
+        return CreateFrame(visual, w, h, dpi);
+    }
+
+    private static VideoFrame Milestone(ChatMessage e, double t, int w, int h)
+    {
+        var dpi = 96.0;
+        var visual = new DrawingVisual();
+        using (var ctx = visual.RenderOpen())
+        {
+            var margin = Math.Max(w, h) * 0.04;
+            var cardW = w - margin * 2;
+            var cardH = h - margin * 2;
+            var cardCX = w / 2.0;
+
+            var enter = Clamp01(t / EnterEnd);
+            var exit = Clamp01((t - ExitStart) / (1 - ExitStart));
+            var cardY = Lerp(h + cardH, margin, EaseOutCubic(enter));
+            cardY = Lerp(cardY, -cardH, EaseInCubic(exit));
+
+            DrawCard(ctx, margin, cardY, cardW, cardH, "#431407", "#c2410c", 14);
+            DrawBrand(ctx, margin, cardY, cardW, cardH);
+
+            var hero = e.MilestoneMonths > 0 ? $"{e.MilestoneMonths}" : "MILESTONE";
+            DrawCentered(ctx, hero, cardCX, cardY + cardH * 0.26, cardH * 0.30, FontWeights.Bold, Color.FromRgb(0xff, 0xdd, 0x66), cardW * 0.8);
+
+            var sub = e.MilestoneMonths > 0 ? "MONTHS STRONG" : "SUPPORTING THE STREAM";
+            DrawCentered(ctx, sub, cardCX, cardY + cardH * 0.52, cardH * 0.11, FontWeights.SemiBold, White, cardW * 0.9);
+            DrawCentered(ctx, "— " + e.AuthorName + " —", cardCX, cardY + cardH * 0.70, cardH * 0.10, FontWeights.Normal, Color.FromRgb(0xff, 0xe8, 0xd0), cardW * 0.9);
+
+            // Tenure bar: grows through the first half, retracts on exit.
+            var barP = Clamp01((t - 0.10) / 0.55) * (1 - exit);
+            var barW = cardW * 0.6 * barP;
+            ctx.DrawRoundedRectangle(
+                new SolidColorBrush(Color.FromRgb(0xff, 0xd1, 0x66)),
+                null,
+                new Rect(cardCX - barW / 2, cardY + cardH * 0.84, barW, cardH * 0.045),
+                4, 4);
+        }
+        return CreateFrame(visual, w, h, dpi);
+    }
+
+    // ─── Shared drawing ───
+
+    private static void DrawCard(DrawingContext ctx, double x, double y, double w, double h, string fromHex, string toHex, double radius)
+    {
+        var brush = new LinearGradientBrush(ParseColor(fromHex), ParseColor(toHex), new Point(0, 0), new Point(1, 1));
+        ctx.DrawRoundedRectangle(brush, new Pen(new SolidColorBrush(Color.FromArgb(0x66, 0xff, 0xff, 0xff)), Math.Max(1, radius * 0.06)), new Rect(x, y, w, h), radius, radius);
+    }
+
+    private static void DrawBrand(DrawingContext ctx, double x, double y, double w, double h)
+    {
+        var formatted = new FormattedText(
+            Brand, Invariant, FlowDirection.LeftToRight,
+            new Typeface(new FontFamily("Segoe UI"), FontStyles.Normal, FontWeights.Normal, FontStretches.Normal),
+            Math.Max(9, h * 0.055),
+            new SolidColorBrush(Color.FromArgb(0x88, 0xff, 0xff, 0xff)),
+            96.0);
+        ctx.DrawText(formatted, new Point(x + w - formatted.Width - h * 0.08, y + h - formatted.Height - h * 0.05));
+    }
+
+    private static void DrawCentered(DrawingContext ctx, string text, double cx, double cy, double size, FontWeight weight, Color color, double maxWidth)
+    {
+        var formatted = new FormattedText(
+            text, Invariant, FlowDirection.LeftToRight,
+            new Typeface(new FontFamily("Segoe UI"), FontStyles.Normal, weight, FontStretches.Normal),
+            size,
+            new SolidColorBrush(color),
+            96.0);
+        formatted.MaxTextWidth = maxWidth;
+        formatted.MaxLineCount = 1;
+        formatted.Trimming = TextTrimming.CharacterEllipsis;
+        ctx.DrawText(formatted, new Point(cx - formatted.Width / 2, cy - formatted.Height / 2));
+    }
+
+    private static Color ParseColor(string hex)
+    {
+        hex = hex.Trim().TrimStart('#');
+        if (hex.Length == 6)
+        {
+            var r = byte.Parse(hex.AsSpan(0, 2), NumberStyles.HexNumber);
+            var g = byte.Parse(hex.AsSpan(2, 2), NumberStyles.HexNumber);
+            var b = byte.Parse(hex.AsSpan(4, 2), NumberStyles.HexNumber);
+            return Color.FromRgb(r, g, b);
+        }
+        if (hex.Length == 8)
+        {
+            var a = byte.Parse(hex.AsSpan(0, 2), NumberStyles.HexNumber);
+            var r = byte.Parse(hex.AsSpan(2, 2), NumberStyles.HexNumber);
+            var g = byte.Parse(hex.AsSpan(4, 2), NumberStyles.HexNumber);
+            var b = byte.Parse(hex.AsSpan(6, 2), NumberStyles.HexNumber);
+            return Color.FromArgb(a, r, g, b);
+        }
+        return Colors.White;
+    }
+
+    private static VideoFrame CreateFrame(DrawingVisual visual, int width, int height, double dpi)
+    {
+        var rtb = new RenderTargetBitmap(width, height, dpi, dpi, PixelFormats.Pbgra32);
+        rtb.Render(visual);
+
+        var stride = width * 4;
+        var pixels = new byte[stride * height];
+        rtb.CopyPixels(pixels, stride, 0);
+
+        for (var i = 0; i < pixels.Length; i += 4)
+        {
+            (pixels[i], pixels[i + 2]) = (pixels[i + 2], pixels[i]);
+        }
+
+        return new VideoFrame(width, height, pixels);
+    }
+
+    private static double Clamp01(double v) => Math.Clamp(v, 0.0, 1.0);
+
+    private static double Lerp(double a, double b, double p) => a + (b - a) * p;
+
+    private static double EaseInCubic(double p) => p * p * p;
+
+    private static double EaseOutCubic(double p) => 1 - Math.Pow(1 - p, 3);
+
+    private static double EaseOutBack(double p)
+    {
+        const double c1 = 1.70158;
+        const double c3 = c1 + 1;
+        return 1 + c3 * Math.Pow(p - 1, 3) + c1 * Math.Pow(p - 1, 2);
+    }
+}

Services/Audio/AudioGainProvider.cs

@@ -28,8 +28,12 @@ public sealed class AudioGainProvider
     /// <summary>Mic gain for the live mix (0 = muted).</summary>
     public double MicGain() => _micMuted() ? 0 : _micVolume();
 
-    /// <summary>Loopback (desktop/game) gain for the live mix (0 = muted, 1 = unity).
-    /// Unity because the slider now drives system volume via PushSystemVolume,
-    /// so the WASAPI loopback signal is already scaled by the user's volume choice.</summary>
-    public double LoopbackGain() => _gameMuted() ? 0 : 1.0;
+    /// <summary>Loopback (desktop/game) gain for the live mix (0 = muted).
+    /// Honesty rule (2026-09-01): WASAPI loopback capture does NOT shrink with the
+    /// endpoint volume — the creator dropped system volume to 20% and the captured
+    /// level stayed pegged — so the mixer must multiply by GameAudioVolume itself
+    /// for the stream to follow the knob (the old unity assumption left the stream
+    /// at full desktop volume while the headphones went quiet; ai.md always
+    /// specified loopbackGain = GameAudioVolume — the code had drifted).</summary>
+    public double LoopbackGain() => _gameMuted() ? 0 : _gameVolume();
 }

Services/Audio/AudioLevelMeter.cs

@@ -16,18 +16,20 @@ public sealed class AudioLevelMeter
 
     /// <summary>
     /// Maps a linear level (0..1) onto the meter's display scale: -60 dBFS..0 dBFS
-    /// spread linearly across 0..1, with +10 dB of input amplification. Linear RMS
-    /// of real speech or game audio is ~0.01..0.1 (-40..-20 dBFS), which leaves a
-    /// flat (linear) meter looking dead; the log scale makes typical levels occupy
-    /// the bar and the amplification pushes real speech peaks into the red zone
-    /// (0.8+) at maxed volume instead of hovering at its edge. Inputs at or below
-    /// -60 dBFS (0.001 linear) read as zero — the meter never idles on background noise.
+    /// spread linearly across 0..1 — an HONEST dBFS scale. Linear RMS of real speech is
+    /// ~0.01..0.1 (-40..-20 dBFS), which leaves a flat (linear) meter looking dead; the
+    /// log scale makes typical levels occupy the bar. Inputs at or below -60 dBFS
+    /// (0.001 linear) read as zero — the meter never idles on background noise.
+    /// <para>2026-10-09: the +10 dB "input amplification" that used to sit here is gone.
+    /// It made a −30 dBFS voice look dialed in, and a creator's upload came out at
+    /// −28.5 LUFS. The speech leveler now puts voice at −20 dBFS, which lands at 2/3 of
+    /// the bar (the green/yellow edge); loud peaks reach the red.</para>
     /// </summary>
     public static float ToDisplay(float linear)
     {
         if (linear <= 0.001f)
             return 0f;
-        var db = 20f * MathF.Log10(linear) + 10f;
+        var db = 20f * MathF.Log10(linear);
         return Math.Clamp(1f + db / 60f, 0f, 1f);
     }
 

Services/Audio/AudioMixer.cs

@@ -1,3 +1,4 @@
+using ytLive.Helpers;
 using ytLive.Services;
 
 namespace ytLive.Services.Audio;
@@ -13,7 +14,9 @@ namespace ytLive.Services.Audio;
 /// queues, applies the honest gains (mic = MicVolume, loopback = unity
 /// × auto-duck when the mic is hot — the slider drives system volume via mixes them to stereo float, runs the
 /// master limiter (a -1 dBFS ceiling so the sum never clips the encoder), and
-/// writes the chunk to the encoder's audio pipe.
+/// writes the chunk to the encoder's audio pipe. Since TASK 47 the alert layer's
+/// clip audio joins the same mix (pre-scaled, unity-added, never ducked) through
+/// <see cref="EnqueueAlertAudio"/>.
 /// </summary>
 public sealed class AudioMixer : IDisposable
 {
@@ -29,12 +32,16 @@ public sealed class AudioMixer : IDisposable
     private readonly Func<double>? _micGain;
     private readonly Func<double>? _loopbackGain;
     private readonly TimeSpan _mixInterval;
+    private readonly Func<int>? _syncOffsetMs;
+    private readonly AudioSyncDelay _syncDelay;
+    private int _advanceSamplesRemaining;
     private bool _started;
 
     // Live path (TASK 9): per-source resampling → voice chain on the mic →
     // thread-safe queues → the ducker + gain/mix loop → the encoder's pipe.
     private readonly AudioRingBuffer _micBuffer;
     private readonly AudioRingBuffer _loopbackBuffer;
+    private readonly AudioRingBuffer _alertBuffer;
     private readonly VoiceFilterChain _voiceChain;
     private readonly AutoDucker _ducker;
     private readonly MasterLimiter _masterLimiter = new();
@@ -44,7 +51,14 @@ public sealed class AudioMixer : IDisposable
     private NamedPipeAudioWriter _pipe = new();
     private float[]? _micChunk;
     private float[]? _loopbackChunk;
+    private float[]? _alertChunk;
     private float[]? _mixBuffer;
+    private float[]? _delayedMix;
+    private DateTime _lastLoopErrorLogged = DateTime.MinValue;
+    private DateTime _nextStatsLog = DateTime.UtcNow + TimeSpan.FromSeconds(5);
+    private long _micDrainedTotal;
+    private long _loopDrainedTotal;
+    private float _peakMix;
 
     public AudioMixer(
         IAudioSource mic,
@@ -52,6 +66,7 @@ public sealed class AudioMixer : IDisposable
         Action<string>? log = null,
         Func<double>? micGain = null,
         Func<double>? loopbackGain = null,
+        Func<int>? syncOffsetMs = null,
         TimeSpan? mixInterval = null)
     {
         _mic = mic;
@@ -61,17 +76,22 @@ public sealed class AudioMixer : IDisposable
         _log = log;
         _micGain = micGain;
         _loopbackGain = loopbackGain;
+        _syncOffsetMs = syncOffsetMs;
+        _syncDelay = new AudioSyncDelay(OutputSampleRate);
         _mixInterval = mixInterval ?? DefaultMixInterval;
 
         var seconds = _mixInterval.TotalSeconds;
         var framesPerTick = Math.Max(1, (int)Math.Round(OutputSampleRate * seconds));
         _micBuffer = new AudioRingBuffer(OutputSampleRate * 2);
         _loopbackBuffer = new AudioRingBuffer(OutputSampleRate * 2 * 2);
+        _alertBuffer = new AudioRingBuffer(OutputSampleRate * 2 * 8);
         _voiceChain = new VoiceFilterChain(OutputSampleRate);
         _ducker = new AutoDucker();
         _micChunk = new float[framesPerTick];
         _loopbackChunk = new float[framesPerTick * 2];
+        _alertChunk = new float[framesPerTick * 2];
         _mixBuffer = new float[framesPerTick * 2];
+        _delayedMix = new float[framesPerTick * 2];
 
         _mic.Started += OnMicStarted;
         _mic.SampleReady += OnMicSample;
@@ -146,19 +166,48 @@ public sealed class AudioMixer : IDisposable
         if (_liveCts != null)
             return;
 
+        // Capture runs from app STARTUP for the meters, so both rings carry up
+        // to a full ring depth (~2s) of pre-live backlog by the time the user
+        // hits record; draining it made every recorded event land ~2s late in
+        // the audio track (2026-09-14, two confirmed takes). Discard it so the
+        // recording starts at go-live. The writers keep running concurrently;
+        // Clear under the ring's lock, so only the in-flight chunk is dropped.
+        _micBuffer.Clear();
+        _loopbackBuffer.Clear();
+        _alertBuffer.Clear();
+
+        // Negative sync offset (audio runs BEHIND video): OBS's fix is to "eat
+        // the head of the buffer" — discard the first |N| ms of the live stream
+        // so every subsequent audio event lands |N| ms EARLIER in the recording.
+        // Armed once at go-live (you can't eat the head mid-stream); positive
+        // offsets stay live-reactive through the delay line in FillAndMix.
+        var syncMs = _syncOffsetMs?.Invoke() ?? 0;
+        _advanceSamplesRemaining = syncMs < 0
+            ? (int)Math.Round(OutputSampleRate / 1000.0 * -syncMs) * 2
+            : 0;
+        if (_advanceSamplesRemaining > 0)
+            _log?.Invoke($"Audio live: advance armed ({-syncMs} ms ahead)");
+
         var cts = new CancellationTokenSource();
         _liveCts = cts;
         _pipe = new NamedPipeAudioWriter();
         _pipe.Start(pipeName);
+        _log?.Invoke($"Audio live: started, pipe '{pipeName}'");
         _ = Task.Run(() => LiveLoopAsync(_pipe, cts.Token));
     }
 
     /// <summary>Ends the live mix loop and closes the audio pipe — ffmpeg sees
-    /// EOF on the audio input. Safe when not live.</summary>
+    /// EOF on the audio input. Safe when not live: the writer's Stop() is idempotent
+    /// (StopStream now calls this on every rollback path).</summary>
     public void StopLive()
     {
-        _liveCts?.Cancel();
+        var cts = _liveCts;
         _liveCts = null;
+        if (cts != null)
+        {
+            _log?.Invoke("Audio live: stopped");
+            cts.Cancel();
+        }
         _pipe.Stop();
     }
 
@@ -204,6 +253,34 @@ public sealed class AudioMixer : IDisposable
         LoopbackLevelChanged?.Invoke(level);
     }
 
+    /// <summary>Drops the alert clip's audio into its own ring (TASK 47 — the
+    /// stream-alert video's soundtrack, pre-scaled by the alert layer to
+    /// volume × fade). Mixed at unity into the live output — NO auto-duck: an
+    /// alert must be heard over the mic, so the Creator's per-alert volume
+    /// slider is the honest gain and nothing else is stacked on top. Monno and
+    /// non-48k sources are normalized (the decoder already emits 48k stereo).</summary>
+    public void EnqueueAlertAudio(AudioSample sample)
+    {
+        var data = sample.Samples;
+        if (data.Length == 0) return;
+        if (sample.SampleRate != OutputSampleRate)
+            data = ResampleLoopback(data, sample.SampleRate);
+        if (sample.Channels == 1)
+            data = UpmixToStereo(data);
+        _alertBuffer.Write(data);
+    }
+
+    private static float[] UpmixToStereo(float[] mono)
+    {
+        var stereo = new float[mono.Length * 2];
+        for (var i = 0; i < mono.Length; i++)
+        {
+            stereo[i * 2] = mono[i];
+            stereo[i * 2 + 1] = mono[i];
+        }
+        return stereo;
+    }
+
     private void OnMicFailed(Exception ex)
     {
         _log?.Invoke($"Mic capture failed: {ex.Message}");
@@ -263,8 +340,42 @@ public sealed class AudioMixer : IDisposable
             var nextTick = DateTime.UtcNow + _mixInterval;
             try
             {
-                FillAndMix(micChunk, loopbackChunk, mixBuffer);
-                await pipe.WriteAsync(mixBuffer, cancellationToken).ConfigureAwait(false);
+                var (_, micDrained, loopDrained) = FillAndMix(micChunk, loopbackChunk, mixBuffer);
+
+                // Negative offset: skip the armed |N| ms of stream head. The pipe
+                // writer tolerates a partial chunk (any float length is valid);
+                // dropping the head re-anchors the audio stream against the video
+                // stream, making each event land earlier — OBS's eat-the-head fix.
+                var writeFrom = 0;
+                if (_advanceSamplesRemaining > 0)
+                {
+                    var drop = Math.Min(_advanceSamplesRemaining, mixBuffer.Length);
+                    _advanceSamplesRemaining -= drop;
+                    writeFrom = drop;
+                }
+
+                if (writeFrom < mixBuffer.Length)
+                    await pipe.WriteAsync(mixBuffer.AsMemory(writeFrom), cancellationToken).ConfigureAwait(false);
+
+                _micDrainedTotal += micDrained;
+                _loopDrainedTotal += loopDrained;
+                for (var i = writeFrom; i < mixBuffer.Length; i++)
+                {
+                    var abs = Math.Abs(mixBuffer[i]);
+                    if (abs > _peakMix) _peakMix = abs;
+                }
+
+                var now = DateTime.UtcNow;
+                if (now >= _nextStatsLog && _log != null)
+                {
+                    _nextStatsLog = now + TimeSpan.FromSeconds(5);
+                    _log($"Audio live: pipe connected={pipe.IsConnected} dropped writes={pipe.DroppedWrites} " +
+                         $"micLevel={_meter.Level:F3} loopLevel={_loopbackMeter.Level:F3} " +
+                         $"drained {_micDrainedTotal:N0}/{_loopDrainedTotal:N0} samples peakMix {_peakMix:F3} (per 5s)");
+                    _micDrainedTotal = 0;
+                    _loopDrainedTotal = 0;
+                    _peakMix = 0;
+                }
             }
             catch (OperationCanceledException)
             {
@@ -272,8 +383,19 @@ public sealed class AudioMixer : IDisposable
             }
             catch (Exception ex)
             {
+                // Throttled + never on a dead session: the 2026-09-01 first-launch flood
+                // was one logged NRE every 10ms tick (see _delayedMix fix). Log at most
+                // once per 5s, and stop looping if the pipe writer is gone for good.
+                if (cancellationToken.IsCancellationRequested)
+                    break;
+                var now = DateTime.UtcNow;
+                if (now - _lastLoopErrorLogged >= TimeSpan.FromSeconds(5))
+                {
+                    _lastLoopErrorLogged = now;
+                    AppLog.Write(ex, "Audio live loop error");
                     _log?.Invoke($"Audio live loop error: {ex.Message}");
                 }
+            }
 
             var delay = nextTick - DateTime.UtcNow;
             if (delay > TimeSpan.Zero)
@@ -291,11 +413,16 @@ public sealed class AudioMixer : IDisposable
     }
 
     /// <summary>Drains one tick's worth of mic + loopback, silence-fills any
-    /// underrun, applies the ducker and the honest gains, and mixes to stereo.</summary>
-    private float FillAndMix(float[] micChunk, float[] loopbackChunk, float[] mix)
+    /// underrun, applies the ducker and the honest gains, and mixes to stereo.
+    /// Returns the pre-duck mic RMS and how many samples each buffer contributed
+    /// (the 5s live-loop telemetry reads those to name whether capture or the
+    /// pipe starved a silent recording).</summary>
+    private (float MicRms, int MicDrained, int LoopDrained) FillAndMix(float[] micChunk, float[] loopbackChunk, float[] mix)
     {
         var micCount = _micBuffer.Read(micChunk, micChunk.Length);
         var loopCount = _loopbackBuffer.Read(loopbackChunk, loopbackChunk.Length);
+        var alertChunk = _alertChunk!;
+        var alertCount = _alertBuffer.Read(alertChunk, alertChunk.Length);
 
         float micRms = 0;
         if (micCount == 0)
@@ -321,6 +448,15 @@ public sealed class AudioMixer : IDisposable
             Array.Clear(loopbackChunk, loopCount, loopbackChunk.Length - loopCount);
         }
 
+        if (alertCount == 0)
+        {
+            Array.Clear(alertChunk, 0, alertChunk.Length);
+        }
+        else if (alertCount < alertChunk.Length)
+        {
+            Array.Clear(alertChunk, alertCount, alertChunk.Length - alertCount);
+        }
+
         var duck = _ducker.Update(micRms);
         var micGain = (float)(_micGain?.Invoke() ?? 1.0);
         var loopGain = (float)(_loopbackGain?.Invoke() ?? 1.0) * duck;
@@ -329,10 +465,17 @@ public sealed class AudioMixer : IDisposable
         for (var i = 0; i < frames; i++)
         {
             var m = micChunk[i] * micGain;
-            mix[i * 2] = m + loopbackChunk[i * 2] * loopGain;
-            mix[i * 2 + 1] = m + loopbackChunk[i * 2 + 1] * loopGain;
+            mix[i * 2] = m + loopbackChunk[i * 2] * loopGain + alertChunk[i * 2];
+            mix[i * 2 + 1] = m + loopbackChunk[i * 2 + 1] * loopGain + alertChunk[i * 2 + 1];
         }
         _masterLimiter.Process(mix);
-        return micRms;
+
+        _syncDelay.Configure(_syncOffsetMs?.Invoke() ?? 0);
+        var delayed = _delayedMix;
+        if (delayed is null || delayed.Length < mix.Length)
+            delayed = _delayedMix = new float[mix.Length];
+        _syncDelay.Process(mix, delayed);
+        Array.Copy(delayed, mix, mix.Length);
+        return (micRms, micCount, loopCount);
     }
 }

Services/Audio/AudioSyncDelay.cs

@@ -0,0 +1,94 @@
+using System;
+
+namespace ytLive.Services.Audio;
+
+/// <summary>
+/// TASK 22: a fixed end-to-end audio delay applied to the interleaved stereo
+/// mix in <see cref="AudioMixer"/>. This is OBS's documented fix for the
+/// "audio is ahead of video" lip-sync case: delay the audio by a few
+/// milliseconds so it lands on the video. It is a pure delay line — input in,
+/// the same audio N ms later out — so it is trivially testable and carries no
+/// state outside its own ring.
+///
+/// Positive offsets only (0..500 ms). Advancing audio (the audio runs BEHIND
+/// the video) is handled upstream in <see cref="AudioMixer"/>, not here: the
+/// mixer eats the first |N| ms of the live stream head (OBS's negative sync —
+/// see <see cref="AudioMixer.StartLive"/>), keeping this line a pure delay.
+/// Changing the delay flushes the line, so a live slider change clicks rather
+/// than smearing. Safe to call from any thread — the mixer owns it.
+/// </summary>
+public sealed class AudioSyncDelay
+{
+    private readonly int _sampleRate;
+
+    private float[] _buffer = Array.Empty<float>();
+    private int _delaySamples;
+    private int _writePos;
+
+    public AudioSyncDelay(int sampleRate)
+    {
+        _sampleRate = Math.Max(1, sampleRate);
+        Configure(0);
+    }
+
+    /// <summary>Sets the delay in whole milliseconds (clamped to 0..500). A no-op
+    /// when the delay hasn't actually changed — <see cref="AudioMixer.FillAndMix"/>
+    /// calls this every ~10ms tick (it re-reads the live UI setting each mix), and
+    /// unconditionally reallocating+zeroing the line every tick (the 2026-09-12
+    /// total-silence bug: any non-zero saved offset wiped the ring before its own
+    /// delayed samples could ever be read back — mic/loop meters, sampled BEFORE
+    /// this stage, kept showing real levels while the pipe stayed pure silence)
+    /// discarded the entire buffered history every 10ms. Changing the delay still
+    /// flushes the line (a live slider change clicks rather than smearing).</summary>
+    public void Configure(int delayMs)
+    {
+        var delaySamples = Frames(delayMs);
+        if (delaySamples == _delaySamples && _buffer.Length > 0) return;
+        _delaySamples = delaySamples;
+        _buffer = new float[(_delaySamples + _sampleRate) * 2 + 1024];
+        _writePos = 0;
+    }
+
+    /// <summary>Delays an interleaved stereo chunk by the configured offset.
+    /// The returned length equals <paramref name="input"/>'s; the head is
+    /// silence until the line fills.</summary>
+    public void Process(ReadOnlySpan<float> input, Span<float> output)
+    {
+        if (output.Length < input.Length)
+            throw new ArgumentException("output must be at least as long as input", nameof(output));
+
+        var len = input.Length;
+        if (_delaySamples == 0)
+        {
+            input.CopyTo(output);
+            return;
+        }
+
+        var line = _buffer;
+        var lineLen = line.Length;
+        for (var i = 0; i < len; i++)
+        {
+            line[_writePos] = input[i];
+            _writePos++;
+            if (_writePos == lineLen)
+                _writePos = 0;
+        }
+
+        var readStart = (_writePos - _delaySamples - len + lineLen * 2) % lineLen;
+        for (var i = 0; i < len; i++)
+        {
+            var idx = readStart + i;
+            if (idx >= lineLen)
+                idx -= lineLen;
+            output[i] = line[idx];
+        }
+    }
+
+    private int Frames(int delayMs)
+    {
+        var clamped = Math.Clamp(delayMs, 0, 500);
+        // Interleaved stereo: each frame is two samples (L, R), so the delay
+        // in buffer positions is twice the frame count.
+        return (int)Math.Round(_sampleRate / 1000.0 * clamped) * 2;
+    }
+}

Services/Audio/ITraxPlayer.cs

@@ -0,0 +1,14 @@
+namespace ytLive.Services.Audio;
+
+/// <summary>Seam over the TRAX background-music player (<see cref="MusicPlayer"/>) so the
+/// toggle/status-light logic is testable without a real audio device.</summary>
+public interface ITraxPlayer : IDisposable
+{
+    event Action<Exception?>? PlaybackEnded;
+    string? TrackName { get; }
+    bool IsPlaying { get; }
+    float LocalGain { get; set; }
+    void Load(string path);
+    void Play();
+    void Pause();
+}

Services/Audio/MusicPlayer.cs

@@ -11,12 +11,17 @@ namespace ytLive.Services.Audio;
 /// The desktop/game bar's gain and mute scale <see cref="LocalGain"/>, so the
 /// creator hears the game-audio controls work on the music too.
 /// </summary>
-public sealed class MusicPlayer : IDisposable
+public sealed class MusicPlayer : ITraxPlayer
 {
-    /// <summary>The one and only music bed — quiet, no slider (the creator's
-    /// voice must stay on top; game/music loudness is the ducker's job). The
-    /// desktop audio bar scales this via <see cref="LocalGain"/>.</summary>
-    public const float MusicVolume = 0.20f;
+    /// <summary>The one and only music bed — no slider (the creator's voice must stay on
+    /// top; that's the ducker's job, −12 dB while they talk). The desktop audio bar scales
+    /// this via <see cref="LocalGain"/>.
+    /// <para>2026-10-09: was 0.20 (−14 dB) — "even at max volume I can barely discern it".
+    /// The creator's track masters at −11.3 LUFS (typical: −9..−14), so 0.20 put the bed at
+    /// ~−25 LUFS, and ducked under speech ~−37 LUFS: inaudible on stream too, because the
+    /// loopback carries exactly what plays locally. 0.5 (−6 dB) lands a typical master at
+    /// ~−15..−20 LUFS — beside the leveled voice (≈ −17 LUFS), and well under it when ducked.</para></summary>
+    public const float MusicVolume = 0.5f;
 
     private MediaFoundationReader? _reader;
     private VolumeWaveProvider16? _volume;

Services/Audio/NamedPipeAudioWriter.cs

@@ -17,6 +17,12 @@ public interface IAudioPipeWriter : IDisposable
     /// <summary>True once ffmpeg has connected and the pipe is writable.</summary>
     bool IsConnected { get; }
 
+    /// <summary>Count of <see cref="WriteAsync"/> calls that wrote nothing because
+    /// the pipe wasn't connected yet or was already closed. Part of the silent-
+    /// recording diagnosis: nonzero means audio was dropped before ffmpeg ever
+    /// connected to the pipe.</summary>
+    long DroppedWrites { get; }
+
     /// <summary>Writes interleaved float samples; dropped until the client connects.</summary>
     Task WriteAsync(ReadOnlyMemory<float> samples, CancellationToken cancellationToken = default);
 
@@ -29,6 +35,9 @@ public sealed class NamedPipeAudioWriter : IAudioPipeWriter
     private readonly object _sync = new();
     private NamedPipeServerStream? _pipe;
 
+    /// <inheritdoc/>
+    public long DroppedWrites { get; private set; }
+
     public void Start(string pipeName)
     {
         lock (_sync)
@@ -64,7 +73,11 @@ public sealed class NamedPipeAudioWriter : IAudioPipeWriter
             pipe = _pipe;
         }
         if (pipe == null || !pipe.IsConnected || samples.IsEmpty)
+        {
+            if (pipe?.IsConnected == false || pipe == null)
+                DroppedWrites++;
             return;
+        }
 
         var bytes = MemoryMarshal.AsBytes(samples.Span).ToArray();
         await pipe.WriteAsync(bytes, cancellationToken).ConfigureAwait(false);

Services/Audio/VoiceFilterChain.cs

@@ -3,15 +3,21 @@ namespace ytLive.Services.Audio;
 /// <summary>
 /// The always-on voice processing chain for the mic (TASK 9 audio milestone).
 /// Pure, per-sample, unit-tested: bass boost → treble lift → noise gate →
-/// compressor. Applied BEFORE the meter and the stream mix so what the creator
-/// hears on the meter is what viewers hear — and so background hum is gated
-/// out before it reaches the encoder.
+/// <b>speech leveler</b> → compressor. Applied BEFORE the meter and the stream mix so
+/// what the creator sees on the meter is what viewers hear — and so background hum
+/// is gated out before it reaches the encoder.
+/// <para>The leveler (2026-10-09) is the gain stage the chain was missing: a creator's
+/// upload measured −28.5 LUFS against YouTube's −14 reference because nothing ever
+/// brought quiet speech UP — the compressor only folds peaks above −6 dBFS and the
+/// master limiter only caps at −1 dBFS. Compressor → gain → limiter is the standard
+/// streaming voice chain.</para>
 /// </summary>
 public sealed class VoiceFilterChain
 {
     private readonly LowShelfFilter _bass;
     private readonly HighShelfFilter _treble;
     private readonly NoiseGate _gate;
+    private readonly SpeechLeveler _leveler;
     private readonly Compressor _compressor;
 
     /// <param name="sampleRate">The (post-resample) mic rate — the RBJ shelf
@@ -21,15 +27,20 @@ public sealed class VoiceFilterChain
         _bass = new LowShelfFilter(sampleRate, 120f, 4f);
         _treble = new HighShelfFilter(sampleRate, 8000f, 3f);
         _gate = new NoiseGate();
+        _leveler = new SpeechLeveler(sampleRate);
         _compressor = new Compressor();
     }
 
+    /// <summary>The leveler's current gain (linear) — for diagnostics and tests.</summary>
+    public float LevelerGain => _leveler.Gain;
+
     public float Process(float sample)
     {
         var bass = _bass.Process(sample);
         var treble = _treble.Process(bass);
         var gated = _gate.Process(treble);
-        return _compressor.Process(gated);
+        var leveled = _leveler.Process(gated, _gate.IsOpen);
+        return _compressor.Process(leveled);
     }
 
     public void Reset()
@@ -37,10 +48,87 @@ public sealed class VoiceFilterChain
         _bass.Reset();
         _treble.Reset();
         _gate.Reset();
+        _leveler.Reset();
         _compressor.Reset();
     }
 }
 
+/// <summary>
+/// Automatic gain for speech: tracks the voice's RMS over ~0.3 s and slowly steers a
+/// gain so speech sits at <see cref="TargetRms"/> (−20 dBFS mono ≈ −17 LUFS once the mic
+/// is mixed to stereo — close to YouTube's −14 reference while leaving the limiter room).
+/// Different mics differ by 20 dB+ in sensitivity; this is what makes "it just sounds
+/// right" true for all of them.
+/// <list type="bullet">
+/// <item>Only learns while the noise gate is open and the voice is above a silence floor —
+/// pauses and background hum never get pumped up.</item>
+/// <item>Gain rises at most <see cref="RiseDbPerSecond"/> and falls at most
+/// <see cref="FallDbPerSecond"/> (faster down than up, so a sudden shout is tamed quickly
+/// and a quiet stretch isn't chased), within <see cref="MinGain"/>..<see cref="MaxGain"/>.</item>
+/// <item>Peaks it pushes up are caught by the <see cref="Compressor"/> after it and the
+/// master limiter at the end of the mix.</item>
+/// </list>
+/// </summary>
+public sealed class SpeechLeveler
+{
+    public const float TargetRms = 0.1f;          // −20 dBFS
+    public const float MaxGain = 10f;             // +20 dB
+    public const float MinGain = 0.5f;            // −6 dB
+    public const float SilenceFloorRms = 0.002f;  // −54 dBFS: below this, hold the gain
+    public const float RiseDbPerSecond = 10f;
+    public const float FallDbPerSecond = 30f;
+    private const float WindowSeconds = 0.3f;
+    private const float UpdateSeconds = 0.01f;
+
+    private readonly float _meanAlpha;
+    private readonly int _updateEvery;
+    private readonly float _maxRiseDb;
+    private readonly float _maxFallDb;
+    private float _meanSquare;
+    private float _gainDb;
+    private float _gain = 1f;
+    private int _sinceUpdate;
+
+    public SpeechLeveler(int sampleRate)
+    {
+        _meanAlpha = 1f / (WindowSeconds * sampleRate);
+        _updateEvery = Math.Max(1, (int)(UpdateSeconds * sampleRate));
+        _maxRiseDb = RiseDbPerSecond * UpdateSeconds;
+        _maxFallDb = FallDbPerSecond * UpdateSeconds;
+    }
+
+    public float Gain => _gain;
+
+    public float Process(float sample, bool voiceActive)
+    {
+        if (voiceActive)
+            _meanSquare += (sample * sample - _meanSquare) * _meanAlpha;
+
+        if (++_sinceUpdate >= _updateEvery)
+        {
+            _sinceUpdate = 0;
+            var rms = MathF.Sqrt(_meanSquare);
+            if (voiceActive && rms > SilenceFloorRms)
+            {
+                var desiredDb = 20f * MathF.Log10(Math.Clamp(TargetRms / rms, MinGain, MaxGain));
+                var step = Math.Clamp(desiredDb - _gainDb, -_maxFallDb, _maxRiseDb);
+                _gainDb += step;
+                _gain = MathF.Pow(10f, _gainDb / 20f);
+            }
+        }
+
+        return sample * _gain;
+    }
+
+    public void Reset()
+    {
+        _meanSquare = 0;
+        _gainDb = 0;
+        _gain = 1f;
+        _sinceUpdate = 0;
+    }
+}
+
 /// <summary>
 /// RBJ audio EQ cookbook low-shelf biquad (bass boost). Transposed direct
 /// form II — stable, cheap, standard.

Services/BackgroundEffects/BackgroundEffectProcessor.cs

@@ -0,0 +1,356 @@
+using ytLive.Helpers;
+using ytLive.Models;
+
+namespace ytLive.Services.BackgroundEffects;
+
+/// <summary>
+/// Applies a webcam's <see cref="BackgroundEffect"/> to one captured frame (TASK 51).
+/// Pure pixel work over the <see cref="VideoFrame"/> seam — WPF-free and thread-agnostic,
+/// so the camera's processing worker can call it before the frame reaches the preview bitmap
+/// and the compositor.
+///
+/// <list type="bullet">
+/// <item><see cref="BackgroundEffect.None"/> returns the SAME frame instance — a true
+/// passthrough, no copy.</item>
+/// <item><see cref="BackgroundEffect.Remove"/> returns a copy whose alpha is the person mask,
+/// RGB untouched, <c>IsOpaque = false</c> — the compositor's straight-alpha blend then shows
+/// the layers below the webcam. Strength = edge softness (0 = crisp cut-out, 1 = the model's
+/// raw soft mask).</item>
+/// <item><see cref="BackgroundEffect.Blur"/> returns a copy where the background is replaced
+/// by a blurred version of itself and the person stays sharp. Strength = blur amount.</item>
+/// </list>
+///
+/// The mask is computed ONCE per camera frame (<see cref="TrySegment"/>) and then rendered for
+/// every effect variant in use (<see cref="Render"/>). A segmenter that returns no mask (or
+/// throws) never drops the layer: the frame passes through and the failure is logged once.
+/// </summary>
+public sealed class BackgroundEffectProcessor
+{
+    public const double DefaultStrength = 0.5;
+
+    /// <summary>The background is blurred at 1/<see cref="BlurDownscale"/> resolution and
+    /// upsampled while blending — a strong blur at a fraction of the cost.</summary>
+    internal const int BlurDownscale = 4;
+
+    /// <summary>Box-blur radius (in downscaled pixels) at strength 0 and 1. The maximum was halved
+    /// from 12 (2026-10-09): the creator found full range too heavy — the old max spread ≈48 full
+    /// px. The established tools blur far less: StreamFX defaults its Box blur size to 5 and its
+    /// author stops downscale-based blurs around 8 px.</summary>
+    internal const int MinBlurRadius = 1;
+    internal const int MaxBlurRadius = 6;
+
+    private readonly IPersonSegmenter _segmenter;
+    private bool _loggedFailure;
+
+    public BackgroundEffectProcessor(IPersonSegmenter segmenter)
+    {
+        _segmenter = segmenter;
+    }
+
+    public VideoFrame Apply(VideoFrame frame, BackgroundEffect effect, double strength = DefaultStrength)
+    {
+        if (effect == BackgroundEffect.None) return frame;
+        var mask = TrySegment(frame);
+        return mask == null ? frame : Render(frame, mask, effect, strength);
+    }
+
+    /// <summary>Runs the segmenter once; null (logged once) when it can't produce a usable mask.</summary>
+    public SegmentationMask? TrySegment(VideoFrame frame)
+    {
+        SegmentationMask? mask;
+        try
+        {
+            mask = _segmenter.Segment(frame);
+        }
+        catch (Exception ex)
+        {
+            LogFailureOnce($"{ex.GetType().Name}: {ex.Message}");
+            return null;
+        }
+
+        if (mask == null || mask.Width < 1 || mask.Height < 1 || mask.Values.Length < mask.Width * mask.Height)
+        {
+            LogFailureOnce("segmenter returned no usable mask");
+            return null;
+        }
+        return mask;
+    }
+
+    public static VideoFrame Render(VideoFrame frame, SegmentationMask mask, BackgroundEffect effect, double strength)
+    {
+        var s = Math.Clamp(strength, 0, 1);
+        return effect switch
+        {
+            BackgroundEffect.Remove => ApplyRemove(frame, mask, s),
+            BackgroundEffect.Blur => ApplyBlur(frame, mask, s),
+            _ => frame,
+        };
+    }
+
+    internal static VideoFrame ApplyRemove(VideoFrame frame, SegmentationMask mask, double strength)
+    {
+        var src = frame.BgraPixels;
+        var dst = new byte[src.Length];
+        Buffer.BlockCopy(src, 0, dst, 0, src.Length);
+
+        // Edge feather: map the mask's [0.5 - w, 0.5 + w] band to alpha 0..1, as a 256-entry LUT
+        // over the quantized mask value (so the per-pixel work is a lookup + one multiply).
+        var w = 0.05 + 0.45 * strength;
+        var lo = 0.5 - w;
+        var span = 2 * w;
+        var alphaLut = new int[256];
+        for (var i = 0; i < 256; i++)
+            alphaLut[i] = (int)Math.Round(Math.Clamp((i / 255.0 - lo) / span, 0, 1) * 256);
+
+        var width = frame.Width;
+        var height = frame.Height;
+        var stride = frame.Stride;
+        var maskRows = UpsampleMaskRows(mask, width);
+        var (r0, r1, fy) = AxisLut(mask.Height, height);
+
+        Parallel.For(0, height, RowParallelism, y =>
+        {
+            var a0 = maskRows[r0[y]];
+            var a1 = maskRows[r1[y]];
+            var t = fy[y];
+            var row = y * stride + 3;
+            for (var x = 0; x < width; x++)
+            {
+                var m = a0[x] + (a1[x] - a0[x]) * t;
+                var q = (int)(m * 255f + 0.5f);
+                q = q < 0 ? 0 : q > 255 ? 255 : q;
+                var p = row + x * 4;
+                dst[p] = (byte)((src[p] * alphaLut[q] + 128) >> 8);
+            }
+        });
+
+        return new VideoFrame(width, height, dst) { Epoch = frame.Epoch, IsOpaque = false };
+    }
+
+    internal static VideoFrame ApplyBlur(VideoFrame frame, SegmentationMask mask, double strength)
+    {
+        var width = frame.Width;
+        var height = frame.Height;
+        var src = frame.BgraPixels;
+        var stride = frame.Stride;
+
+        // 1. Downscale by box-averaging BlurDownscale×BlurDownscale blocks (3 float channels).
+        var f = BlurDownscale;
+        var sw = (width + f - 1) / f;
+        var sh = (height + f - 1) / f;
+        var small = new float[sw * sh * 3];
+        Parallel.For(0, sh, RowParallelism, sy =>
+        {
+            var y0 = sy * f;
+            var y1 = Math.Min(height, y0 + f);
+            for (var sx = 0; sx < sw; sx++)
+            {
+                var x0 = sx * f;
+                var x1 = Math.Min(width, x0 + f);
+                float b = 0, g = 0, r = 0;
+                var n = 0;
+                for (var y = y0; y < y1; y++)
+                {
+                    var p = y * stride + x0 * 4;
+                    for (var x = x0; x < x1; x++, p += 4)
+                    {
+                        b += src[p]; g += src[p + 1]; r += src[p + 2];
+                        n++;
+                    }
+                }
+                var o = (sy * sw + sx) * 3;
+                small[o] = b / n; small[o + 1] = g / n; small[o + 2] = r / n;
+            }
+        });
+
+        // 2. Three separable box-blur passes ≈ a gaussian.
+        var radius = BlurRadius(strength);
+        var scratch = new float[small.Length];
+        for (var pass = 0; pass < 3; pass++)
+        {
+            BoxBlurHorizontal(small, scratch, sw, sh, radius);
+            BoxBlurVertical(scratch, small, sw, sh, radius);
+        }
+
+        // 3. Upsample: horizontal interpolation precomputed once per small row (and per mask row),
+        //    then each output row lerps two precomputed rows — no per-pixel 2-D bilinear.
+        var blurRows = UpsampleColorRows(small, sw, sh, width);
+        var (b0, b1, bfy) = AxisLut(sh, height);
+        var maskRows = UpsampleMaskRows(mask, width);
+        var (m0, m1, mfy) = AxisLut(mask.Height, height);
+
+        // 4. Blend: person (mask) keeps the source pixel, background takes the blur.
+        var dst = new byte[src.Length];
+        Parallel.For(0, height, RowParallelism, y =>
+        {
+            var ma = maskRows[m0[y]];
+            var mb = maskRows[m1[y]];
+            var mt = mfy[y];
+            var ba = blurRows[b0[y]];
+            var bb = blurRows[b1[y]];
+            var bt = bfy[y];
+            var row = y * stride;
+            for (var x = 0; x < width; x++)
+            {
+                var p = row + x * 4;
+                var m = ma[x] + (mb[x] - ma[x]) * mt;
+                if (m >= 0.999f)
+                {
+                    dst[p] = src[p]; dst[p + 1] = src[p + 1]; dst[p + 2] = src[p + 2]; dst[p + 3] = src[p + 3];
+                    continue;
+                }
+                if (m < 0f) m = 0f;
+                var k = 1f - m;
+                var c = x * 3;
+                var vb = ba[c] + (bb[c] - ba[c]) * bt;
+                var vg = ba[c + 1] + (bb[c + 1] - ba[c + 1]) * bt;
+                var vr = ba[c + 2] + (bb[c + 2] - ba[c + 2]) * bt;
+                dst[p] = ClampByte(src[p] * m + vb * k);
+                dst[p + 1] = ClampByte(src[p + 1] * m + vg * k);
+                dst[p + 2] = ClampByte(src[p + 2] * m + vr * k);
+                dst[p + 3] = src[p + 3];
+            }
+        });
+
+        return new VideoFrame(width, height, dst) { Epoch = frame.Epoch, IsOpaque = frame.IsOpaque };
+    }
+
+    /// <summary>Blur radius in downscaled pixels for a strength. Quadratic (s²), not linear, so the
+    /// default 0.5 stays gentle (2 small px ≈ ~8–10 full px of perceived spread, ~3× lighter than
+    /// the old linear 6) while only the top of the slider approaches the full range.</summary>
+    internal static int BlurRadius(double strength)
+    {
+        var s = Math.Clamp(strength, 0, 1);
+        return (int)Math.Round(MinBlurRadius + (MaxBlurRadius - MinBlurRadius) * s * s);
+    }
+
+    /// <summary>Row-parallel pixel loops, capped so the effect worker can't starve the compositor
+    /// and encoder threads.</summary>
+    private static readonly ParallelOptions RowParallelism = new()
+    {
+        MaxDegreeOfParallelism = Math.Clamp(Environment.ProcessorCount / 2, 1, 4),
+    };
+
+    private static byte ClampByte(float v)
+    {
+        var i = (int)(v + 0.5f);
+        return (byte)(i < 0 ? 0 : i > 255 ? 255 : i);
+    }
+
+    /// <summary>For each destination index along one axis: the two source indices and the
+    /// fractional weight — pixel-center aligned, edge-clamped (the same mapping a bilinear
+    /// sample uses).</summary>
+    private static (int[] I0, int[] I1, float[] F) AxisLut(int srcSize, int dstSize)
+    {
+        var i0 = new int[dstSize];
+        var i1 = new int[dstSize];
+        var fr = new float[dstSize];
+        for (var d = 0; d < dstSize; d++)
+        {
+            var s = (d + 0.5f) * srcSize / dstSize - 0.5f;
+            var a = (int)MathF.Floor(s);
+            var t = s - a;
+            i0[d] = Math.Clamp(a, 0, srcSize - 1);
+            i1[d] = Math.Clamp(a + 1, 0, srcSize - 1);
+            fr[d] = a < 0 ? 0f : a + 1 > srcSize - 1 ? 0f : t;
+        }
+        return (i0, i1, fr);
+    }
+
+    /// <summary>Each mask row, horizontally interpolated (and clamped to 0..1) to the frame width.</summary>
+    private static float[][] UpsampleMaskRows(SegmentationMask mask, int width)
+    {
+        var (x0, x1, fx) = AxisLut(mask.Width, width);
+        var rows = new float[mask.Height][];
+        var v = mask.Values;
+        for (var r = 0; r < mask.Height; r++)
+        {
+            var row = new float[width];
+            var o = r * mask.Width;
+            for (var x = 0; x < width; x++)
+            {
+                var a = v[o + x0[x]];
+                var m = a + (v[o + x1[x]] - a) * fx[x];
+                row[x] = m < 0f ? 0f : m > 1f ? 1f : m;
+            }
+            rows[r] = row;
+        }
+        return rows;
+    }
+
+    /// <summary>Each row of a 3-channel float image, horizontally interpolated to <paramref name="width"/>.</summary>
+    private static float[][] UpsampleColorRows(float[] img, int w, int h, int width)
+    {
+        var (x0, x1, fx) = AxisLut(w, width);
+        var rows = new float[h][];
+        Parallel.For(0, h, RowParallelism, r =>
+        {
+            var row = new float[width * 3];
+            var o = r * w;
+            for (var x = 0; x < width; x++)
+            {
+                var a = (o + x0[x]) * 3;
+                var b = (o + x1[x]) * 3;
+                var t = fx[x];
+                row[x * 3] = img[a] + (img[b] - img[a]) * t;
+                row[x * 3 + 1] = img[a + 1] + (img[b + 1] - img[a + 1]) * t;
+                row[x * 3 + 2] = img[a + 2] + (img[b + 2] - img[a + 2]) * t;
+            }
+            rows[r] = row;
+        });
+        return rows;
+    }
+
+    private static void BoxBlurHorizontal(float[] input, float[] output, int w, int h, int r)
+    {
+        var norm = 1f / (2 * r + 1);
+        for (var y = 0; y < h; y++)
+        {
+            var row = y * w;
+            for (var c = 0; c < 3; c++)
+            {
+                float sum = 0;
+                for (var i = -r; i <= r; i++)
+                    sum += input[(row + Math.Clamp(i, 0, w - 1)) * 3 + c];
+                for (var x = 0; x < w; x++)
+                {
+                    output[(row + x) * 3 + c] = sum * norm;
+                    var add = Math.Min(w - 1, x + r + 1);
+                    var sub = Math.Max(0, x - r);
+                    sum += input[(row + add) * 3 + c] - input[(row + sub) * 3 + c];
+                }
+            }
+        }
+    }
+
+    private static void BoxBlurVertical(float[] input, float[] output, int w, int h, int r)
+    {
+        var norm = 1f / (2 * r + 1);
+        for (var x = 0; x < w; x++)
+        {
+            for (var c = 0; c < 3; c++)
+            {
+                float sum = 0;
+                for (var i = -r; i <= r; i++)
+                    sum += input[(Math.Clamp(i, 0, h - 1) * w + x) * 3 + c];
+                for (var y = 0; y < h; y++)
+                {
+                    output[(y * w + x) * 3 + c] = sum * norm;
+                    var add = Math.Min(h - 1, y + r + 1);
+                    var sub = Math.Max(0, y - r);
+                    sum += input[(add * w + x) * 3 + c] - input[(sub * w + x) * 3 + c];
+                }
+            }
+        }
+    }
+
+
+
+
+    private void LogFailureOnce(string reason)
+    {
+        if (_loggedFailure) return;
+        _loggedFailure = true;
+        AppLog.Write($"BackgroundEffectProcessor: passing webcam through — {reason}");
+    }
+}

Services/BackgroundEffects/IPersonSegmenter.cs

@@ -0,0 +1,13 @@
+namespace ytLive.Services.BackgroundEffects;
+
+/// <summary>A person-probability mask at the segmenter's own resolution: row-major,
+/// one value per pixel, 0 = background, 1 = person.</summary>
+public sealed record SegmentationMask(int Width, int Height, float[] Values);
+
+/// <summary>Seam over the person-segmentation model (TASK 51) so tests inject a fake and
+/// never run real inference. Returns null when no mask can be produced; callers then pass
+/// the frame through untouched.</summary>
+public interface IPersonSegmenter
+{
+    SegmentationMask? Segment(VideoFrame frame);
+}

Services/BackgroundEffects/MaskSmoother.cs

@@ -0,0 +1,68 @@
+namespace ytLive.Services.BackgroundEffects;
+
+/// <summary>
+/// Temporal smoothing for the person mask (TASK 51): each raw frame's segmentation is blended
+/// with the previous smoothed mask so the cut-out edge doesn't flutter from frame to frame when
+/// the model's per-frame verdict wavers.
+///
+/// Blend = <see cref="CurrentWeight"/> × new + (1 − <see cref="CurrentWeight"/>) × previous.
+/// Weights come from the established tools rather than a guess: OBS's obs-backgroundremoval
+/// smoke-tests `temporal_smooth_factor` at its 0.85 default, and Jitsi's webcam background
+/// filter (jitsi/jitsi-meet#17080) found 0.7/0.3 transformed best — a midpoint that still
+/// reacts to real movement. 0.5/0.5 is worse: on motion it leaves a smearing edge ghost.
+///
+/// State lives per camera session (the <see cref="CameraManager"/>'s one-per-frame worker), NOT
+/// in the segmenter — the segmenter is shared app-wide and its contract test pins the raw
+/// per-frame mask.
+/// </summary>
+public sealed class MaskSmoother
+{
+    /// <summary>Weight of the newest raw mask; the rest is the previous smoothed mask.</summary>
+    internal const double CurrentWeight = 0.75;
+
+    private float[]? _current;
+    private float[]? _scratch;
+    private int _width;
+    private int _height;
+    private bool _hasHistory;
+
+    /// <summary>
+    /// Returns the temporally-smoothed mask. A null input (segmenter hiccup) resets history so
+    /// the next real mask starts moving again; the first frame and any size change pass through
+    /// un-blended, and the returned mask never aliases the caller's array (the first frame copies
+    /// its history). The two buffers ping-pong so no per-frame allocation is needed — a 256×144
+    /// mask is 147 KB, past the 85 KB LOH threshold.
+    /// </summary>
+    public SegmentationMask? Smooth(SegmentationMask? raw)
+    {
+        if (raw == null)
+        {
+            _hasHistory = false;
+            _width = 0;
+            _height = 0;
+            return null;
+        }
+
+        if (!_hasHistory || _width != raw.Width || _height != raw.Height
+            || _current == null || _scratch == null)
+        {
+            _width = raw.Width;
+            _height = raw.Height;
+            _current = new float[raw.Values.Length];
+            _scratch = new float[raw.Values.Length];
+            Array.Copy(raw.Values, _current, raw.Values.Length);
+            _hasHistory = true;
+            return raw;
+        }
+
+        var v = raw.Values;
+        var next = _scratch;
+        var keep = 1f - (float)CurrentWeight;
+        for (var i = 0; i < v.Length; i++)
+            next[i] = keep * _current[i] + (float)CurrentWeight * v[i];
+
+        _scratch = _current;
+        _current = next;
+        return new SegmentationMask(_width, _height, next);
+    }
+}

Services/BackgroundEffects/OnnxPersonSegmenter.cs

@@ -0,0 +1,107 @@
+using System.IO;
+using Microsoft.ML.OnnxRuntime;
+using ytLive.Helpers;
+
+namespace ytLive.Services.BackgroundEffects;
+
+/// <summary>
+/// The default <see cref="IPersonSegmenter"/>: Google's MediaPipe Selfie Segmenter
+/// (landscape, Apache-2.0) converted to ONNX by <c>tools/selfie-seg/</c> and shipped as an
+/// embedded resource — nothing is downloaded at runtime and no GPU is required.
+///
+/// Contract: input [1,144,256,3] RGB in [0,1] (NHWC), output [1,144,256,1] person
+/// probability. The whole frame is resampled to 256×144 (stretched, not cropped), so the
+/// mask maps back to the frame by normalized coordinates.
+///
+/// Never throws from <see cref="Segment"/>: a model that fails to load or run logs once
+/// and returns null, and the caller passes the webcam frame through.
+/// </summary>
+public sealed class OnnxPersonSegmenter : IPersonSegmenter, IDisposable
+{
+    public const int ModelWidth = 256;
+    public const int ModelHeight = 144;
+    internal const string ModelResourceName = "ytLive.Assets.Models.selfie_segmenter_landscape.onnx";
+
+    private static readonly long[] InputShape = { 1, ModelHeight, ModelWidth, 3 };
+
+    private readonly object _gate = new();
+    private readonly float[] _input = new float[ModelWidth * ModelHeight * 3];
+    private readonly RunOptions _runOptions = new();
+    private InferenceSession? _session;
+    private bool _failed;
+    private bool _disposed;
+
+    public SegmentationMask? Segment(VideoFrame frame)
+    {
+        lock (_gate)
+        {
+            if (_failed || _disposed) return null;
+            try
+            {
+                _session ??= CreateSession();
+                FillInput(frame, _input);
+                using var input = OrtValue.CreateTensorValueFromMemory(_input, InputShape);
+                using var outputs = _session.Run(_runOptions, new[] { "input" }, new[] { input }, new[] { "mask" });
+                var mask = outputs[0].GetTensorDataAsSpan<float>().ToArray();
+                return new SegmentationMask(ModelWidth, ModelHeight, mask);
+            }
+            catch (Exception ex)
+            {
+                _failed = true;
+                AppLog.Write($"OnnxPersonSegmenter: background effects disabled — {ex.GetType().Name}: {ex.Message}");
+                return null;
+            }
+        }
+    }
+
+    public void Dispose()
+    {
+        lock (_gate)
+        {
+            _disposed = true;
+            _session?.Dispose();
+            _session = null;
+            _runOptions.Dispose();
+        }
+    }
+
+    private static InferenceSession CreateSession()
+    {
+        using var stream = typeof(OnnxPersonSegmenter).Assembly.GetManifestResourceStream(ModelResourceName)
+            ?? throw new InvalidOperationException($"embedded model '{ModelResourceName}' is missing");
+        using var buffer = new MemoryStream();
+        stream.CopyTo(buffer);
+        // Two intra-op threads: the model is tiny, and the webcam must not starve the
+        // compositor/encoder threads (obs-backgroundremoval reports 2 as the sweet spot).
+        using var options = new SessionOptions
+        {
+            IntraOpNumThreads = 2,
+            InterOpNumThreads = 1,
+            GraphOptimizationLevel = GraphOptimizationLevel.ORT_ENABLE_ALL,
+        };
+        return new InferenceSession(buffer.ToArray(), options);
+    }
+
+    /// <summary>BGRA frame → model input: nearest-sample stretch to 256×144, RGB order,
+    /// values /255. Nearest is enough — the model input is ~5× smaller than a 720p frame
+    /// and the mask is the only thing that comes back.</summary>
+    internal static void FillInput(VideoFrame frame, float[] input)
+    {
+        var src = frame.BgraPixels;
+        var stride = frame.Stride;
+        var o = 0;
+        for (var y = 0; y < ModelHeight; y++)
+        {
+            var sy = Math.Min(frame.Height - 1, (int)((y + 0.5) * frame.Height / ModelHeight));
+            var row = sy * stride;
+            for (var x = 0; x < ModelWidth; x++)
+            {
+                var sx = Math.Min(frame.Width - 1, (int)((x + 0.5) * frame.Width / ModelWidth));
+                var p = row + sx * 4;
+                input[o++] = src[p + 2] / 255f;
+                input[o++] = src[p + 1] / 255f;
+                input[o++] = src[p] / 255f;
+            }
+        }
+    }
+}

Services/BackgroundEffects/WebcamEffectKey.cs

@@ -0,0 +1,16 @@
+using ytLive.Models;
+
+namespace ytLive.Services.BackgroundEffects;
+
+/// <summary>Identifies one rendered variant of a camera's frames (TASK 51): the effect plus its
+/// strength, rounded to 2 decimals so a slider drag doesn't spawn a variant per pixel of travel.
+/// <see cref="BackgroundEffect.None"/> always normalizes to strength 0 — the raw path.</summary>
+public readonly record struct WebcamEffectKey(BackgroundEffect Effect, double Strength)
+{
+    public static WebcamEffectKey None => new(BackgroundEffect.None, 0);
+
+    public static WebcamEffectKey For(BackgroundEffect effect, double strength)
+        => effect == BackgroundEffect.None
+            ? None
+            : new WebcamEffectKey(effect, Math.Round(Math.Clamp(strength, 0, 1), 2));
+}

Services/CameraManager.cs

@@ -6,6 +6,8 @@ using System.Windows.Media;
 using System.Windows.Media.Imaging;
 using System.Windows.Threading;
 using ytLive.Helpers;
+using ytLive.Models;
+using ytLive.Services.BackgroundEffects;
 
 namespace ytLive.Services;
 
@@ -21,9 +23,24 @@ namespace ytLive.Services;
 /// <paramref name="firstFrameTimeout"/>), and an async <see cref="SourceFailed"/>
 /// tears the session down and surfaces <see cref="CameraFailed"/> — no silent
 /// empty box.
+///
+/// Background effects (TASK 51) are the ONE processing point on the camera path: per device,
+/// the set of requested <see cref="WebcamEffectKey"/>s (<see cref="SetRequestedEffects"/>) is
+/// rendered from each raw frame on a background worker — one segmentation per frame, smoothed
+/// per camera across frames (see <see cref="MaskSmoother"/>) and shared by every variant,
+/// latest-frame-drop when the worker is busy — and each variant keeps its own
+/// latest frame (the compositor) and shared WriteableBitmap (the preview). The raw path is
+/// untouched, so a slow or failing model never stalls the plain webcam.
 /// </summary>
 public sealed class CameraManager : IDisposable
 {
+    private sealed class EffectVariant
+    {
+        public WriteableBitmap? PreviewBitmap;
+        public VideoFrame? LatestFrame;
+        public bool FramePending;
+    }
+
     private sealed class CameraSession
     {
         public string DeviceId { get; }
@@ -36,6 +53,10 @@ public sealed class CameraManager : IDisposable
         public VideoFrame? LatestFrame;
         public bool FramePending;
         public TaskCompletionSource<bool>? FirstFrame;
+        public readonly Dictionary<WebcamEffectKey, EffectVariant> Effects = new();
+        public bool EffectWorkerRunning;
+        public VideoFrame? LastEffectSource;
+        public readonly MaskSmoother Smoother = new();
 
         public CameraSession(string deviceId, ICameraFrameSource source)
         {
@@ -50,11 +71,18 @@ public sealed class CameraManager : IDisposable
     private readonly Dispatcher? _uiDispatcher;
     private readonly TimeSpan _firstFrameTimeout;
     private readonly Dictionary<string, CameraSession> _sessions = new();
+    private readonly Dictionary<string, HashSet<WebcamEffectKey>> _requestedEffects = new();
     private readonly object _gate = new();
+    private readonly BackgroundEffectProcessor? _effects;
+    private readonly EffectTimer _effectTimer = new();
 
     /// <summary>Raised on the UI thread when a camera's shared preview bitmap is first created.</summary>
     public event Action<string, WriteableBitmap>? PreviewBitmapChanged;
 
+    /// <summary>Raised on the UI thread when an effect variant's preview bitmap is first created
+    /// (device id, effect key, bitmap) — the effect counterpart of <see cref="PreviewBitmapChanged"/>.</summary>
+    public event Action<string, WebcamEffectKey, WriteableBitmap>? EffectPreviewBitmapChanged;
+
     /// <summary>
     /// Raised when a capture fails: device in use, access denied, no preview source,
     /// or a started reader that never delivers a first frame within the timeout.
@@ -62,12 +90,55 @@ public sealed class CameraManager : IDisposable
     public event Action<string, string>? CameraFailed;
 
     public CameraManager(ICameraEnumerator enumerator, Func<string, ICameraFrameSource> frameSourceFactory,
-        Dispatcher? uiDispatcher = null, TimeSpan? firstFrameTimeout = null)
+        Dispatcher? uiDispatcher = null, TimeSpan? firstFrameTimeout = null,
+        BackgroundEffectProcessor? effects = null)
     {
         _enumerator = enumerator;
         _frameSourceFactory = frameSourceFactory;
         _uiDispatcher = uiDispatcher;
         _firstFrameTimeout = firstFrameTimeout ?? TimeSpan.FromSeconds(4);
+        _effects = effects;
+    }
+
+    /// <summary>
+    /// Declares which background-effect variants a device must render (the union over every
+    /// scene's webcam config). <see cref="BackgroundEffect.None"/> keys are ignored — that's the
+    /// raw path. Variants no longer requested are dropped (their worker cost stops); new ones
+    /// start rendering from the next camera frame. Survives the session starting later.
+    /// </summary>
+    public void SetRequestedEffects(string deviceId, IEnumerable<WebcamEffectKey> keys)
+    {
+        if (string.IsNullOrWhiteSpace(deviceId)) return;
+        lock (_gate)
+        {
+            var set = new HashSet<WebcamEffectKey>();
+            foreach (var key in keys)
+                if (key.Effect != BackgroundEffect.None) set.Add(key);
+            _requestedEffects[deviceId] = set;
+            if (_sessions.TryGetValue(deviceId, out var session))
+                SyncVariants(session, set);
+        }
+    }
+
+    /// <summary>The latest frame for a variant: the raw frame for <see cref="BackgroundEffect.None"/>,
+    /// otherwise the processed frame — null until the first one is rendered (an un-processed
+    /// frame is never shown in its place, so Remove never flashes the real room).</summary>
+    public VideoFrame? GetLatestFrame(string deviceId, WebcamEffectKey key)
+    {
+        if (key.Effect == BackgroundEffect.None) return GetLatestFrame(deviceId);
+        lock (_gate)
+            return _sessions.TryGetValue(deviceId, out var session)
+                && session.Effects.TryGetValue(key, out var variant) ? variant.LatestFrame : null;
+    }
+
+    /// <summary>The shared preview bitmap for a variant (raw bitmap for None), or null until
+    /// its first frame — then <see cref="EffectPreviewBitmapChanged"/> fires.</summary>
+    public WriteableBitmap? GetPreviewBitmap(string deviceId, WebcamEffectKey key)
+    {
+        if (key.Effect == BackgroundEffect.None) return GetPreviewBitmap(deviceId);
+        lock (_gate)
+            return _sessions.TryGetValue(deviceId, out var session)
+                && session.Effects.TryGetValue(key, out var variant) ? variant.PreviewBitmap : null;
     }
 
     public ICameraEnumerator Enumerator => _enumerator;
@@ -94,6 +165,8 @@ public sealed class CameraManager : IDisposable
                 session.Source.FrameAvailable += session.FrameHandler;
                 session.FailureHandler = message => OnSourceFailed(session, message);
                 session.Source.SourceFailed += session.FailureHandler;
+                if (_requestedEffects.TryGetValue(deviceId, out var requested))
+                    SyncVariants(session, requested);
                 _sessions[deviceId] = session;
                 shouldStart = true;
             }
@@ -171,6 +244,18 @@ public sealed class CameraManager : IDisposable
         toStop.PreviewBitmap = null;
     }
 
+    /// <summary>
+    /// True while a session exists for the device — started, or still starting.
+    /// Used by the app's startup resource check to avoid double-acquiring a lock
+    /// that the saved identity's scene configs already hold. A rolled-back (failed)
+    /// session is removed, so this goes false and the startup pass can retry.
+    /// </summary>
+    public bool IsRunning(string deviceId)
+    {
+        lock (_gate)
+            return _sessions.ContainsKey(deviceId);
+    }
+
     public VideoFrame? GetLatestFrame(string deviceId)
     {
         lock (_gate)
@@ -265,6 +350,7 @@ public sealed class CameraManager : IDisposable
         if (!TryGetActiveSession(session)) return;
         session.LatestFrame = frame;
         session.FirstFrame?.TrySetResult(true);
+        ScheduleEffects(session);
 
         if (session.PreviewBitmap == null)
         {
@@ -296,6 +382,142 @@ public sealed class CameraManager : IDisposable
         }, DispatcherPriority.Render);
     }
 
+    // Caller holds _gate. A new key inherits the last frame + bitmap of a dropped variant with
+    // the SAME effect (a strength change), so neither the stream nor the preview blanks for a
+    // frame while the creator drags the strength slider.
+    private static void SyncVariants(CameraSession session, HashSet<WebcamEffectKey> keys)
+    {
+        var dropped = session.Effects.Where(kv => !keys.Contains(kv.Key)).ToList();
+        foreach (var (stale, _) in dropped)
+            session.Effects.Remove(stale);
+        foreach (var key in keys)
+        {
+            if (session.Effects.ContainsKey(key)) continue;
+            var heir = dropped.FirstOrDefault(kv => kv.Key.Effect == key.Effect).Value;
+            session.Effects[key] = new EffectVariant
+            {
+                LatestFrame = heir?.LatestFrame,
+                PreviewBitmap = heir?.PreviewBitmap,
+            };
+        }
+    }
+
+    private void ScheduleEffects(CameraSession session)
+    {
+        if (_effects == null) return;
+        lock (_gate)
+        {
+            if (session.Effects.Count == 0 || session.EffectWorkerRunning) return;
+            session.EffectWorkerRunning = true;
+        }
+        _ = Task.Run(() => RunEffectWorker(session));
+    }
+
+    /// <summary>Renders every requested variant from the newest raw frame, then loops while a
+    /// newer frame has arrived; exits (and re-arms on the next frame) when caught up. One
+    /// segmentation per processed frame, whatever the number of variants.</summary>
+    private void RunEffectWorker(CameraSession session)
+    {
+        try
+        {
+            while (true)
+            {
+                VideoFrame? source;
+                List<WebcamEffectKey> keys;
+                lock (_gate)
+                {
+                    source = session.LatestFrame;
+                    if (!TryGetActiveSessionLocked(session) || session.Effects.Count == 0
+                        || source == null || ReferenceEquals(source, session.LastEffectSource))
+                    {
+                        session.EffectWorkerRunning = false;
+                        return;
+                    }
+                    session.LastEffectSource = source;
+                    keys = session.Effects.Keys.ToList();
+                }
+
+                var started = System.Diagnostics.Stopwatch.GetTimestamp();
+                var mask = session.Smoother.Smooth(_effects!.TrySegment(source));
+                var rendered = new List<(WebcamEffectKey Key, VideoFrame Frame)>(keys.Count);
+                if (mask != null)
+                    foreach (var key in keys)
+                        rendered.Add((key, BackgroundEffectProcessor.Render(source, mask, key.Effect, key.Strength)));
+                _effectTimer.Record(System.Diagnostics.Stopwatch.GetElapsedTime(started), source, keys.Count);
+
+                foreach (var (key, frame) in rendered)
+                {
+                    EffectVariant? variant;
+                    lock (_gate)
+                    {
+                        if (session.Effects.TryGetValue(key, out variant))
+                            variant.LatestFrame = frame;
+                    }
+                    if (variant != null) PublishVariantPreview(session, key, variant);
+                }
+            }
+        }
+        catch (Exception ex)
+        {
+            lock (_gate) session.EffectWorkerRunning = false;
+            AppLog.Write($"CameraManager: background effects worker failed: {ex.GetType().Name}: {ex.Message}");
+        }
+    }
+
+    private void PublishVariantPreview(CameraSession session, WebcamEffectKey key, EffectVariant variant)
+    {
+        if (_uiDispatcher == null) return;
+        lock (_gate)
+        {
+            if (variant.FramePending) return;
+            variant.FramePending = true;
+        }
+        _uiDispatcher.BeginInvoke(() =>
+        {
+            VideoFrame? frame;
+            lock (_gate)
+            {
+                variant.FramePending = false;
+                if (!TryGetActiveSessionLocked(session) || !session.Effects.TryGetValue(key, out var current)
+                    || !ReferenceEquals(current, variant)) return;
+                frame = variant.LatestFrame;
+            }
+            if (frame == null) return;
+            var bitmap = variant.PreviewBitmap;
+            if (bitmap == null || bitmap.PixelWidth != frame.Width || bitmap.PixelHeight != frame.Height)
+            {
+                bitmap = new WriteableBitmap(frame.Width, frame.Height, 96, 96, PixelFormats.Bgra32, null);
+                bitmap.WritePixels(new Int32Rect(0, 0, frame.Width, frame.Height), frame.BgraPixels, frame.Stride, 0);
+                variant.PreviewBitmap = bitmap;
+                EffectPreviewBitmapChanged?.Invoke(session.DeviceId, key, bitmap);
+                return;
+            }
+            bitmap.WritePixels(new Int32Rect(0, 0, frame.Width, frame.Height), frame.BgraPixels, frame.Stride, 0);
+        }, DispatcherPriority.Render);
+    }
+
+    private bool TryGetActiveSessionLocked(CameraSession session)
+        => _sessions.TryGetValue(session.DeviceId, out var current) && ReferenceEquals(current, session);
+
+    /// <summary>Perf record for the creator's-box check (TASK 51): logs the average
+    /// segment + render cost once per session after 120 processed frames.</summary>
+    private sealed class EffectTimer
+    {
+        private int _count;
+        private double _totalMs;
+        private bool _logged;
+
+        public void Record(TimeSpan elapsed, VideoFrame frame, int variants)
+        {
+            if (_logged) return;
+            _totalMs += elapsed.TotalMilliseconds;
+            if (++_count < 120) return;
+            _logged = true;
+            AppLog.Write($"CameraManager: background effects avg {_totalMs / _count:0.0} ms/frame " +
+                         $"({frame.Width}x{frame.Height}, {variants} variant(s), {_count} frames)");
+        }
+    }
+
     private void EnsurePreviewBitmap(CameraSession session)
     {
         if (session.PreviewBitmap != null || session.LatestFrame == null) return;

Services/ChannelStatsService.cs

@@ -0,0 +1,132 @@
+using System.Net.Http;
+using System.Text.Json;
+using ytLive.Models;
+using AppLog = ytLive.Helpers.AppLog;
+
+namespace ytLive.Services;
+
+/// <summary>
+/// Pulls a connected channel's YPP-relevant numbers from the YouTube Data API
+/// (TASK 39, slice 1): subscriptions/views/videos via channels.list, and the
+/// count of public uploads in the trailing 90 days via playlistItems.list on the
+/// uploads playlist. Long-form watch hours and Shorts-feed views need the
+/// Analytics API (a later slice behind the IChannelStatsProvider seam).
+///
+/// NOTE (root cause, 2026-09-23): channels.list must NOT request the
+/// `auditDetails` part — that part alone requires the
+/// `youtubepartner-channel-audit` scope the app doesn't (and mustn't) hold, and
+/// the whole request 403s `insufficientPermissions` over it. Standing flags are
+/// not exposed to ordinary apps; the drawer deep-links to YouTube Studio instead.
+/// </summary>
+public class ChannelStatsService
+{
+    private readonly YouTubeAuthService _auth;
+    private readonly HttpClient _http;
+    private const string ApiBase = "https://www.googleapis.com/youtube/v3";
+
+    public ChannelStatsService(YouTubeAuthService auth, HttpClient? http = null)
+    {
+        _auth = auth;
+        _http = http ?? new HttpClient();
+    }
+
+    private async Task<bool> EnsureToken()
+    {
+        if (_auth.CurrentChannel == null) return false;
+        if (_auth.CurrentChannel.TokenExpiry <= DateTime.UtcNow.AddMinutes(5))
+            return await _auth.RefreshToken();
+        return true;
+    }
+
+    /// <summary>Captures the channel's current stats into a snapshot, or null when
+    /// there's no session, a request fails, or the API returns nothing. Never throws.</summary>
+    public virtual async Task<YppStatSnapshot?> CaptureCurrentAsync()
+    {
+        if (!await EnsureToken()) return null;
+
+        _http.DefaultRequestHeaders.Authorization = new("Bearer", _auth.CurrentChannel!.AccessToken);
+
+        var response = await _http.GetAsync(
+            $"{ApiBase}/channels?mine=true&part=statistics,contentDetails");
+        if (!response.IsSuccessStatusCode)
+        {
+            // Log the response body: YouTube's error.reason names the failure
+            // (insufficientPermissions / quotaExceeded / …) — the bare code was
+            // undiagnosable for the 2026-09-23 auditDetails 403.
+            var errorBody = await response.Content.ReadAsStringAsync();
+            AppLog.Write($"YPP stats: channels.list failed ({(int)response.StatusCode}): {errorBody}");
+            return null;
+        }
+
+        var json = JsonSerializer.Deserialize<JsonElement>(await response.Content.ReadAsStringAsync());
+        if (!json.TryGetProperty("items", out var items) || items.GetArrayLength() == 0)
+            return null;
+
+        var channel = items[0];
+        var statistics = channel.GetProperty("statistics");
+
+        var uploadsPlaylistId = channel.TryGetProperty("contentDetails", out var contentDetails)
+            && contentDetails.TryGetProperty("relatedPlaylists", out var related)
+            && related.TryGetProperty("uploads", out var uploads)
+            ? uploads.GetString()
+            : null;
+
+        var uploadsLast90Days = uploadsPlaylistId != null
+            ? await CountUploadsLast90DaysAsync(uploadsPlaylistId)
+            : 0;
+
+        return new YppStatSnapshot
+        {
+            CapturedAtUtc = DateTime.UtcNow,
+            SubscriberCount = ReadInt64(statistics, "subscriberCount"),
+            VideoCount = ReadInt64(statistics, "videoCount"),
+            TotalViews = ReadInt64(statistics, "viewCount"),
+            UploadsLast90Days = uploadsLast90Days,
+        };
+    }
+
+    /// <summary>YouTube serializes statistics as JSON STRINGS ("350"); a tolerant
+    /// read that also accepts a number (the real 403 hid this parse bug until the
+    /// auditDetails removal surfaced the string shape in 2026-09-23's Good Dog).
+    /// NOTE: JsonElement.TryGetInt64 THROWS on a non-Number token — ValueKind must
+    /// be checked first (try-type-in, not try-catch).</summary>
+    private static long ReadInt64(JsonElement parent, string name)
+    {
+        if (!parent.TryGetProperty(name, out var value)) return 0;
+        if (value.ValueKind == JsonValueKind.Number && value.TryGetInt64(out var n)) return n;
+        if (value.ValueKind == JsonValueKind.String && long.TryParse(value.GetString(), out n)) return n;
+        return 0;
+    }
+
+    /// <summary>Counts uploads published within the trailing 90 days, scanning the
+    /// most recent 50 from the uploads playlist (generous beyond the 3/90-day YPP
+    /// requirement; the YPP tab labels it as the recent-50 window).</summary>
+    private async Task<int> CountUploadsLast90DaysAsync(string uploadsPlaylistId)
+    {
+        var response = await _http.GetAsync(
+            $"{ApiBase}/playlistItems?part=snippet&playlistId={Uri.EscapeDataString(uploadsPlaylistId)}&maxResults=50");
+        if (!response.IsSuccessStatusCode)
+        {
+            AppLog.Write($"YPP stats: playlistItems.list failed ({(int)response.StatusCode})");
+            return 0;
+        }
+
+        var json = JsonSerializer.Deserialize<JsonElement>(await response.Content.ReadAsStringAsync());
+        if (!json.TryGetProperty("items", out var items)) return 0;
+
+        var cutoff = DateTime.UtcNow.AddDays(-90);
+        var count = 0;
+        foreach (var item in items.EnumerateArray())
+        {
+            if (!item.TryGetProperty("snippet", out var snippet)
+                || !snippet.TryGetProperty("publishedAt", out var published)
+                || !DateTime.TryParse(published.GetString(), out var publishedAt))
+            {
+                continue;
+            }
+            if (publishedAt.ToUniversalTime() >= cutoff)
+                count++;
+        }
+        return count;
+    }
+}

Services/ChatOverlayLayer.cs

@@ -0,0 +1,249 @@
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Threading;
+using ytLive.Helpers;
+using ytLive.Models;
+
+namespace ytLive.Services;
+
+/// <summary>Owns the YouTube-chat overlay behavior: the message buffer, the
+/// renderer, and the fade/mock-preview timers. The MainViewModel keeps only the
+/// thin binding surface (the shared <see cref="Messages"/> collection + two
+/// computed gate props) and hands the scene list in at each call — this class
+/// owns all chat logic so an AI can read one self-contained unit.</summary>
+public sealed class ChatOverlayLayer
+{
+    private readonly ChatBoxRenderer _renderer;
+
+    // Mock chat messages for the ChatBox preview — branded placeholders so the
+    // creator sees where the overlay lands before going live.
+    private static readonly IReadOnlyList<ChatMessage> MockChatMessages = new[]
+    {
+        new ChatMessage { AuthorName = "LlamaCasty", Message = "welcome to the stream!", Timestamp = DateTime.Now.AddMinutes(-4), IsMember = true },
+        new ChatMessage { AuthorName = "LlamaCastyFan", Message = "$10 — LlamaCasty is the best!", Timestamp = DateTime.Now.AddMinutes(-3), IsSuperChat = true },
+        new ChatMessage { AuthorName = "GamerDude", Message = "what streaming software is this?", Timestamp = DateTime.Now.AddMinutes(-2) },
+        new ChatMessage { AuthorName = "LlamaCasty", Message = "thanks for watching! llamacasty.com", Timestamp = DateTime.Now.AddMinutes(-1), IsMember = true },
+        new ChatMessage { AuthorName = "LlamaDog", Message = "Subscribe so they can buy the subscription at llamacasty.com!", Timestamp = DateTime.Now, IsMember = true },
+    };
+
+    // Chat fade timer: clears chat overlay after N seconds of inactivity.
+    private DispatcherTimer? _fadeTimer;
+    private CancellationTokenSource? _mockCts;
+
+    /// <summary>The live chat message buffer. Shared with the ViewModel (which
+    /// binds it to the panel) via <c>ChatMessages =&gt; _chatLayer.Messages</c>.</summary>
+    public ObservableCollection<ChatMessage> Messages { get; } = new();
+
+    // Output-frame cache (take-5 starvation fix): the pump called RenderFrame
+    // every tick and the renderer did a FULL WPF raster (FormattedText +
+    // RenderTargetBitmap + CopyPixels + channel swap) each time — 15-25ms of a
+    // 25.5ms render. Established answer (OBS text sources): raster on change,
+    // blit the cache every tick. _contentVersion bumps on every buffer mutation
+    // (CollectionChanged — covers adds, the 500-cap removal, and the fade
+    // Clear from any caller); the config key covers the box geometry/appearance.
+    // The cached VideoFrame is treated as immutable: the compositor only reads.
+    private int _contentVersion;
+    private int _frameVersion = -1;
+    private string? _frameKey;
+    private VideoFrame? _cachedFrame;
+
+    public ChatOverlayLayer(ChatBoxRenderer renderer)
+    {
+        _renderer = renderer;
+        Messages.CollectionChanged += (_, _) => _contentVersion++;
+    }
+
+    /// <summary>Ingest a message from the poller. UI-thread marshalled: appended
+    /// to the buffer (capped at 500), mock preview stopped, swipe to real
+    /// messages, and the fade timer reset. Scenes are handed in so the layer can
+    /// refresh every ChatBox preview without owning the scene graph.</summary>
+    public void OnMessageReceived(ChatMessage message, IEnumerable<Scene> scenes)
+    {
+        System.Windows.Application.Current.Dispatcher.Invoke(() =>
+        {
+            Messages.Add(message);
+            if (Messages.Count > 500)
+                Messages.RemoveAt(0);
+
+            // Reset chat fade timer on every message
+            ResetChatFadeTimer(scenes);
+
+            StopMockPreview();
+
+            // Switch ChatBox previews from mock to real messages
+            foreach (var chatBox in scenes.SelectMany(s => s.Elements).OfType<Source>()
+                         .Where(s => s.Type == SourceType.ChatBox))
+                UpdatePreview(chatBox);
+        });
+    }
+
+    private void ResetChatFadeTimer(IEnumerable<Scene> scenes)
+    {
+        _fadeTimer?.Stop();
+        var chatBoxes = scenes.SelectMany(s => s.Elements).OfType<Source>()
+            .Where(s => s.Type == SourceType.ChatBox && s.ChatFadeSeconds > 0).ToList();
+        if (chatBoxes.Count == 0) return;
+
+        var delay = chatBoxes.Min(s => s.ChatFadeSeconds);
+        _fadeTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(delay) };
+        _fadeTimer.Tick += (_, _) =>
+        {
+            _fadeTimer?.Stop();
+            _fadeTimer = null;
+            Messages.Clear();
+            foreach (var chatBox in scenes.SelectMany(s => s.Elements).OfType<Source>()
+                         .Where(s => s.Type == SourceType.ChatBox))
+                UpdatePreview(chatBox);
+            StartMockPreview(scenes);
+        };
+        _fadeTimer.Start();
+    }
+
+    /// <summary>Renders the live-output frame for one ChatBox element (the
+    /// compositor path), or null when no messages are buffered yet. Mirrors the
+    /// preview render but without writing onto the source's VideoImageSource.</summary>
+    public VideoFrame? RenderFrame(Source chatBox)
+    {
+        var width = (int)Math.Max(1, chatBox.Width);
+        var height = (int)Math.Max(1, chatBox.Height);
+        var key =
+            $"{width}x{height}|{chatBox.ChatFontSize}|{chatBox.ChatFontFamily}|{chatBox.ChatFontColor}"
+            + $"|{chatBox.ChatBackgroundColor}|{chatBox.ChatMaxMessages}|{chatBox.ChatShowTimestamps}"
+            + $"|{chatBox.ChatShowBadges}|{chatBox.ChatMemberColor}|{chatBox.ChatSuperChatColor}";
+
+        if (_frameKey == key && _frameVersion == _contentVersion)
+            return _cachedFrame; // same content + same config — the cached raster stands
+
+        // The raster is WPF (DrawingVisual + RenderTargetBitmap = UI-thread objects)
+        // and the frame pump now renders from its own thread (take-8 off-UI fix) —
+        // so only the cache CHECK runs off-thread; the rare miss marshals to the
+        // dispatcher and re-validates there (a second message landing mid-hop must
+        // not be answered by a snapshot taken before it).
+        var app = System.Windows.Application.Current;
+        if (app != null && !app.Dispatcher.CheckAccess())
+        {
+            var capturedKey = key;
+            var capturedVersion = _contentVersion;
+            var frame = app.Dispatcher.Invoke(() =>
+            {
+                if (_frameKey == capturedKey && _frameVersion == capturedVersion)
+                    return _cachedFrame; // someone already re-rasterized on the UI thread
+                return RenderCore(chatBox, width, height, capturedKey, capturedVersion);
+            });
+            return frame;
+        }
+
+        return RenderCore(chatBox, width, height, key, _contentVersion);
+    }
+
+    private VideoFrame? RenderCore(Source chatBox, int width, int height, string key, int version)
+    {
+        _frameKey = key;
+        _frameVersion = version;
+        if (Messages.Count == 0) return _cachedFrame = null;
+
+        return _cachedFrame = _renderer.Render(
+            Messages,
+            width,
+            height,
+            chatBox.ChatFontSize,
+            chatBox.ChatFontFamily,
+            chatBox.ChatFontColor,
+            chatBox.ChatBackgroundColor,
+            chatBox.ChatMaxMessages,
+            chatBox.ChatShowTimestamps,
+            chatBox.ChatShowBadges,
+            chatBox.ChatMemberColor,
+            chatBox.ChatSuperChatColor);
+    }
+
+    /// <summary>Renders one ChatBox preview: real messages when connected, mock
+    /// when not. Writes the resulting bitmap onto the source's
+    /// <c>VideoImageSource</c>.</summary>
+    public void UpdatePreview(Source chatBox, IReadOnlyList<ChatMessage>? messages = null)
+    {
+        try
+        {
+            messages ??= Messages.Count > 0 ? (IReadOnlyList<ChatMessage>)Messages : MockChatMessages;
+            var width = (int)Math.Max(32, chatBox.Width);
+            var height = (int)Math.Max(32, chatBox.Height);
+
+            var frame = _renderer.Render(
+                messages,
+                width,
+                height,
+                chatBox.ChatFontSize,
+                chatBox.ChatFontFamily,
+                chatBox.ChatFontColor,
+                chatBox.ChatBackgroundColor,
+                chatBox.ChatMaxMessages,
+                chatBox.ChatShowTimestamps,
+                chatBox.ChatShowBadges,
+                chatBox.ChatMemberColor,
+                chatBox.ChatSuperChatColor);
+
+            var bitmap = new WriteableBitmap(width, height, 96, 96, PixelFormats.Bgra32, null);
+            bitmap.WritePixels(new Int32Rect(0, 0, width, height), frame.BgraPixels, frame.Stride, 0);
+            chatBox.VideoImageSource = bitmap;
+        }
+        catch (Exception ex) { AppLog.Write($"UpdateChatBoxPreview failed: {ex.Message}"); }
+    }
+
+    private async Task RunMockPreviewAsync(Source chatBox, CancellationToken ct)
+    {
+        var n = 0;
+        while (!ct.IsCancellationRequested)
+        {
+            UpdatePreview(chatBox, MockChatMessages.Take(n + 1).ToList());
+            await Task.Delay(1000, ct);
+            n++;
+            if (n == MockChatMessages.Count)
+            {
+                await Task.Delay(3000, ct);
+                n = 0;
+            }
+        }
+    }
+
+    public void StartMockPreview(IEnumerable<Scene> scenes)
+    {
+        StopMockPreview();
+        _mockCts = new CancellationTokenSource();
+        var ct = _mockCts.Token;
+        foreach (var chatBox in scenes.SelectMany(s => s.Elements).OfType<Source>()
+                     .Where(s => s.Type == SourceType.ChatBox && s.ChatPreviewEnabled))
+            _ = RunMockPreviewAsync(chatBox, ct);
+    }
+
+    public void StopMockPreview()
+    {
+        _mockCts?.Cancel();
+        _mockCts?.Dispose();
+        _mockCts = null;
+    }
+
+    /// <summary>Render previews + wire property-change subscriptions for all
+    /// ChatBox sources across every scene. Called after layout load so existing
+    /// ChatBox sources show mock content and respond to config changes.</summary>
+    public void UpdateConfiguredBoxes(IEnumerable<Scene> scenes)
+    {
+        foreach (var scene in scenes)
+            foreach (var chatBox in scene.Elements.OfType<Source>().Where(s => s.Type == SourceType.ChatBox))
+            {
+                chatBox.PropertyChanged += (_, e) =>
+                {
+                    if (e.PropertyName is nameof(Source.ChatFontSize) or nameof(Source.ChatFontColor)
+                        or nameof(Source.ChatBackgroundColor) or nameof(Source.ChatBackgroundOpacity)
+                        or nameof(Source.ChatMaxMessages) or nameof(Source.ChatShowTimestamps)
+                        or nameof(Source.ChatShowBadges) or nameof(Source.ChatMemberColor)
+                        or nameof(Source.ChatSuperChatColor) or nameof(Source.ChatFontFamily)
+                        or nameof(Source.ChatFadeSeconds) or nameof(Source.Width) or nameof(Source.Height))
+                        UpdatePreview(chatBox);
+                };
+                UpdatePreview(chatBox);
+            }
+    }
+}

Services/Compositor/AlertTickerRenderer.cs

@@ -0,0 +1,182 @@
+using System.Collections.Generic;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Threading;
+using ytLive.Models;
+
+namespace ytLive.Services.Compositor;
+
+/// <summary>
+/// Rasterizes the stream-alert ticker into a transparent BGRA strip that the
+/// output compositor overlays along the very top edge of the master frame
+/// (TASK 47). The strip is text ("Viewer — Super Chat · $12.34") inside a dark
+/// pill with the LlamaCasty accent bar, rendered ONCE per unique text on the UI
+/// thread (WPF <c>RenderTargetBitmap</c>, Pbgra32→straight-alpha like
+/// <see cref="SocialBarRenderer"/>), then cached. Each <see cref="Render"/> call
+/// is pure byte-math on that cached raster producing a scrolling marquee frame,
+/// so the frame pump can call it from any thread for every output frame at
+/// 30fps without a Dispatcher round-trip.
+/// </summary>
+public static class AlertTickerRenderer
+{
+    /// <summary>Master-frame width — the ticker spans the full 1920px output.</summary>
+    public const int Width = 1920;
+
+    /// <summary>Strip height (pill + vertical padding).</summary>
+    public const int Height = 48;
+
+    private const int RepeatGap = 120;
+    private const int CacheLimit = 48;
+
+    /// <summary>How long each blink half lasts in <see cref="AlertDisplayMethod.Flash"/>
+    /// (0.5s on, 0.5s off — a 1Hz pulse for the whole alert).</summary>
+    public const double FlashHalfSeconds = 0.5;
+
+    private static readonly object Gate = new();
+    private static readonly Dictionary<string, VideoFrame> StripCache = new();
+
+    /// <summary>A frame of <paramref name="text"/> presented per
+    /// <paramref name="method"/> at <paramref name="elapsedSeconds"/> into the alert,
+    /// or null when there is nothing to show (no text, or a Flash in its off half).
+    /// Thread-safe: reads the cached raster and does row copies only.
+    /// <para><see cref="AlertDisplayMethod.TickerScroll"/> paces itself from
+    /// <paramref name="readsPerAlert"/> over <paramref name="alertSeconds"/> rather
+    /// than a fixed pixels-per-second: the old constant (140px/s ≈ a 17s pass) meant
+    /// a 10s alert showed the text barely once, entering from the right and never
+    /// crossing. The creator's target is three readable passes per alert.</para>
+    /// <para><paramref name="width"/>/<paramref name="height"/> default to the
+    /// full-master strip. They are parameters because the ticker now renders INTO the
+    /// Stream Alerts box (creator ruling 2026-09-26) and therefore has to be the box's
+    /// size: a 1920-wide strip clipped to an 800px box would hide the announcement
+    /// off the right edge for most of its pass, which is the opposite of readable.</para></summary>
+    public static VideoFrame? Render(string? text, double elapsedSeconds,
+        AlertDisplayMethod method = AlertDisplayMethod.TickerScroll,
+        double alertSeconds = 0.0, int readsPerAlert = 3,
+        int width = Width, int height = Height)
+    {
+        if (string.IsNullOrWhiteSpace(text)) return null;
+        if (width <= 0 || height <= 0) return null;
+        var strip = GetStrip(text!);
+        if (strip == null) return null;
+
+        if (method == AlertDisplayMethod.Flash
+            && elapsedSeconds % (FlashHalfSeconds * 2) >= FlashHalfSeconds)
+            return null; // off half of the pulse
+
+        var x = method == AlertDisplayMethod.TickerScroll
+            ? ScrollX(strip.Width, width, elapsedSeconds, alertSeconds, readsPerAlert)
+            : (width - strip.Width) / 2; // Solid + Flash: centred, still
+
+        var pixels = new byte[width * height * 4];
+        CopyStrip(pixels, width, height, strip, x);
+        if (method == AlertDisplayMethod.TickerScroll && x + strip.Width <= 0)
+            CopyStrip(pixels, width, height, strip, x + width + RepeatGap); // wrapped tail enters
+        return new VideoFrame(width, height, pixels);
+    }
+
+    /// <summary>Left edge of the pill for a marquee that must complete
+    /// <paramref name="readsPerAlert"/> passes in <paramref name="alertSeconds"/>:
+    /// one pass (off the right edge, across, out of sight) takes that long.
+    /// <para>The run is phase-started half a frame in, so the very first frame of an
+    /// alert already shows the announcement instead of a blank strip sitting exactly
+    /// off the right edge.</para></summary>
+    private static int ScrollX(int stripWidth, int width, double elapsedSeconds,
+        double alertSeconds, int readsPerAlert)
+    {
+        var cycle = width + stripWidth + RepeatGap;
+        var pass = Math.Max(0.5, alertSeconds) / Math.Max(1, readsPerAlert);
+        var speed = cycle / pass;
+        var pos = (width / 2 + (int)(elapsedSeconds * speed)) % cycle;
+        return width - pos;
+    }
+
+
+    private static void CopyStrip(byte[] dst, int dstW, int dstH, VideoFrame strip, int dstX)
+    {
+        if (dstX >= dstW || dstX + strip.Width <= 0) return;
+        var x0 = Math.Max(0, dstX);
+        var x1 = Math.Min(dstW, dstX + strip.Width);
+        var sx0 = x0 - dstX;
+        var copyBytes = (x1 - x0) * 4;
+        var sw = strip.Width;
+        // The strip is rasterised at its natural 48px; the target box can be shorter,
+        // and copying strip.Height rows into a shorter dst would run off the end of the
+        // array. Clip the rows, not the buffer.
+        var rows = Math.Min(strip.Height, dstH);
+        for (var y = 0; y < rows; y++)
+            Buffer.BlockCopy(strip.BgraPixels, (y * sw + sx0) * 4, dst, (y * dstW + x0) * 4, copyBytes);
+    }
+
+    private static VideoFrame? GetStrip(string text)
+    {
+        lock (Gate)
+        {
+            if (StripCache.TryGetValue(text, out var cached)) return cached;
+        }
+        var strip = RenderStrip(text);
+        if (strip == null) return null;
+        lock (Gate)
+        {
+            if (StripCache.Count >= CacheLimit) StripCache.Clear();
+            if (!StripCache.TryGetValue(text, out var existing))
+                StripCache[text] = strip;
+            return StripCache[text];
+        }
+    }
+
+    private static VideoFrame? RenderStrip(string text)
+    {
+        // WPF rendering is single-threaded; the pump thread resolves to the UI
+        // thread at most once per unique text (then hits the cache).
+        var app = Application.Current;
+        if (app != null && !app.Dispatcher.CheckAccess())
+        {
+            VideoFrame? result = null;
+            app.Dispatcher.Invoke(() => result = RenderStrip(text));
+            return result;
+        }
+
+        const double pillHeight = 34;
+        const double accentW = 6;
+        const double padX = 16;
+        const double gap = 8;
+
+        var font = new Typeface(new FontFamily("Segoe UI"), FontStyles.Normal, FontWeights.SemiBold, FontStretches.Normal);
+        var ft = new FormattedText(text, CultureInfo.InvariantCulture, FlowDirection.LeftToRight,
+            font, 22, Brushes.White, 1.0);
+
+        var pillW = (int)Math.Ceiling(padX + accentW + gap + ft.Width + padX);
+        var top = (Height - pillHeight) / 2.0;
+        var textTop = top + (pillHeight - ft.Height) / 2.0;
+
+        var visual = new DrawingVisual();
+        using (var dc = visual.RenderOpen())
+        {
+            var pill = new Rect(0, top, pillW, pillHeight);
+            dc.DrawRoundedRectangle(new SolidColorBrush(Color.FromArgb(0xE6, 0x10, 0x13, 0x24)), null, pill, pillHeight / 2, pillHeight / 2);
+            dc.DrawRoundedRectangle(new SolidColorBrush(Color.FromRgb(0xe9, 0x45, 0x60)), null,
+                new Rect(padX, top + (pillHeight - 12) / 2.0, accentW, 12), 2, 2);
+            dc.DrawText(ft, new Point(padX + accentW + gap, textTop));
+        }
+
+        var bitmap = new RenderTargetBitmap(pillW, Height, 96, 96, PixelFormats.Pbgra32);
+        bitmap.Render(visual);
+
+        var pixels = new byte[pillW * Height * 4];
+        bitmap.CopyPixels(pixels, pillW * 4, 0);
+
+        // Pbgra32 is premultiplied — unpremultiply so the compositor's
+        // straight-alpha source-over doesn't halo the text edges.
+        for (var i = 0; i < pixels.Length; i += 4)
+        {
+            var a = pixels[i + 3];
+            if (a == 0 || a == 255) continue;
+            pixels[i] = (byte)(pixels[i] * 255 / a);
+            pixels[i + 1] = (byte)(pixels[i + 1] * 255 / a);
+            pixels[i + 2] = (byte)(pixels[i + 2] * 255 / a);
+        }
+        return new VideoFrame(pillW, Height, pixels);
+    }
+}

Services/Compositor/BrandFlashPresenter.cs

@@ -0,0 +1,421 @@
+using System;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Threading;
+
+namespace ytLive.Services.Compositor;
+
+/// <summary>
+/// The free-tier branding flash: a "made with LlamaCasty!" credit that is COMPOSITED
+/// INTO THE OUTPUT (recording or stream), not merely shown in the preview.
+/// <para>2026-09-26. This used to exist only as a WPF <c>BrandFlashLayer</c> in
+/// <c>PreviewPane.xaml</c> — a 0.25-opacity centred TextBlock the creator could see and
+/// no viewer ever could. The compositor has carried an unused <c>flashFrame</c> slot
+/// since then; this type is the producer that finally feeds it. It is wired on the
+/// PER-FRAME path only: <c>SceneGraph.GetBakedBase</c> also accepts a <c>flashFrame</c>,
+/// and that one is a trap — <c>SceneRegion.Matches</c> compares element ids only, so a
+/// flash folded into the baked static base would freeze there and never expire.</para>
+/// <para>The credit is deliberately obnoxious (creator directive 2026-09-26): full-opacity
+/// neon, a different random position every presentation, and a hard sell every 30–60s.
+/// It is gated on LICENCE state, never on a UI toggle — see <see cref="Enabled"/>.</para>
+/// </summary>
+public sealed class BrandFlashPresenter : IDisposable
+{
+    /// <summary>The credit line, kept identical to the old preview TextBlock so the
+    /// wording can never drift between the preview and the broadcast.</summary>
+    public const string Text = "made with LlamaCasty!";
+
+    // Presentation envelope (creator-specified 2026-09-26): 500ms fade in, the credit
+    // held at full opacity for 1000ms, then a 500ms fade out — 2000ms end to end.
+    public const double FadeInSeconds = 0.5;
+    public const double HoldSeconds = 1.0;
+    public const double FadeOutSeconds = 0.5;
+    public const double PresentationSeconds = FadeInSeconds + HoldSeconds + FadeOutSeconds;
+
+    /// <summary>Cadence: <c>rand(0, 30s) + 30s</c> ⇒ a flash every 30–60s, so it never
+    /// lands on a beat a viewer could tune out.</summary>
+    public const int IntervalFloorMs = 30_000;
+    public const int IntervalJitterMs = 30_000;
+
+    /// <summary>The first flash lands shortly after go-live (the stream-start
+    /// impression); the random cadence takes over from there.</summary>
+    public const double FirstFlashDelaySeconds = 5.0;
+
+    /// <summary>Master-space canvas. Global overlays in this codebase are authored at
+    /// master size and scaled by the compositor.</summary>
+    public const int MasterWidth = 1920;
+    public const int MasterHeight = 1080;
+
+    /// <summary>Neon recipe taken from the established overlay look (see commit
+    /// message): a bright near-white CORE plus a feathered multi-radius HALO, with the
+    /// red and blue channels pushed in OPPOSITE directions — Maxon's "Chromatic Glow"
+    /// notes the green channel is all but invisible behind white text once R and B are
+    /// split, which is exactly the look.</summary>
+    private static readonly Color NeonRed = Color.FromRgb(0xe9, 0x45, 0x60);  // brand red, exact
+    private static readonly Color NeonBlue = Color.FromRgb(0x4d, 0x8b, 0xff); // brand blue #0f3460 lifted for luminance
+    private static readonly Color CoreColor = Colors.White;
+
+    /// <summary>Font size chosen so the credit spans roughly half the master width:
+    /// big enough to read as advertising, small enough that the random placement has
+    /// real travel room (a full-width line could only ever sit at x≈0).</summary>
+    private const double FontSize = 120;
+    private const double GlowPadding = 34;
+    private const double TickSeconds = 0.033;
+
+    private readonly Random _random;
+    private readonly DispatcherTimer? _timer;
+    private readonly object _gate = new();
+
+    private bool _enabled = true;
+    private bool _running;
+    private double _sinceStart;
+    private double _nextFlashAt;      // absolute time of the next flash, _sinceStart's reference
+    private double _elapsed;            // seconds into the presentation; >= PresentationSeconds means idle
+    private VideoFrame? _raster;        // tight, full-opacity glowing credit (straight alpha)
+    private byte[]? _buffer;            // reused master-space BGRA — hence the Epoch bump below
+    private int _atX, _atY;
+    private long _epoch;
+
+    public BrandFlashPresenter(Random? random = null)
+    {
+        _random = random ?? new Random();
+        if (Application.Current is { } app)
+        {
+            _timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(TickSeconds) };
+            _timer.Tick += (_, _) => Advance(TickSeconds);
+        }
+    }
+
+    /// <summary>The licence gate, driven by <c>MainViewModel.IsPremium</c> (Polar
+    /// validation) and NOT by a user-facing toggle: once this credit is composited into
+    /// the broadcast it is the thing standing between a paying customer's stream and an
+    /// advertisement, so it is re-checked on every read. A premium user mid-presentation
+    /// loses the flash on the very next tick rather than at the end of the credit.</summary>
+    public bool Enabled
+    {
+        get { lock (_gate) return _enabled; }
+        set
+        {
+            bool restart;
+            lock (_gate)
+            {
+                if (_enabled == value) return;
+                _enabled = value;
+                if (!value)
+                {
+                    // Licence state only ever goes premium → no flash. Cut the current
+                    // presentation short instead of running it out ungated.
+                    _elapsed = PresentationSeconds;
+                    _timer?.Stop();
+                    restart = false;
+                }
+                else
+                {
+                    // …but a DOWNGRADE (key entered mid-session) must bring the cadence
+                    // back. The presenter now runs for the life of the app — Start() is
+                    // called once at startup, not per go-live — so stopping the timer on
+                    // the premium edge without restarting it here would leave the credit
+                    // dead until the process is restarted, even after a valid key.
+                    restart = _running;
+                }
+            }
+            if (restart) _timer?.Start();
+        }
+    }
+
+    /// <summary>True while a credit is on screen (drives the preview's visibility).</summary>
+    public bool IsPresenting
+    {
+        get { lock (_gate) return _enabled && _elapsed < PresentationSeconds; }
+    }
+
+    /// <summary>Test-only: is the <see cref="DispatcherTimer"/> that drives
+    /// <see cref="Advance"/> actually running? The premium/downgrade edge is the only
+    /// thing that ever stops and restarts it now that the presenter is started once for
+    /// the life of the app, and a synchronous test body cannot observe a real timer
+    /// tick — so assert the decision directly instead of sleeping through a 30–60s
+    /// interval. Never call this from product code.</summary>
+    internal bool IsCadenceTimerEnabled => _timer?.IsEnabled ?? false;
+
+    /// <summary>Begin the cadence: first flash <see cref="FirstFlashDelaySeconds"/>
+    /// after the call, then every <c>rand(30s) + 30s</c>.</summary>
+    public void Start()
+    {
+        EnsureRaster();
+        lock (_gate)
+        {
+            _running = true;
+            _sinceStart = 0;
+            _nextFlashAt = FirstFlashDelaySeconds;
+        }
+        if (_enabled) _timer?.Start();
+    }
+
+    public void Stop()
+    {
+        lock (_gate)
+        {
+            _running = false;
+            _elapsed = PresentationSeconds;
+        }
+        _timer?.Stop();
+    }
+
+    /// <summary>Advance the presentation clock. Also the deterministic test seam: tests
+    /// drive this directly and never call <see cref="Start"/>, so no timer is running
+    /// and the clock only moves when the test moves it (mirrors <c>AlertOverlayLayer.Advance</c>).</summary>
+    public void Advance(double deltaSeconds)
+    {
+        // Rasterise BEFORE taking the lock. WPF text formatting is UI-thread affine, so
+        // this can hop to the dispatcher — and a blocking hop while holding _gate would
+        // deadlock against a timer tick that wants the same lock.
+        EnsureRaster();
+
+        lock (_gate)
+        {
+            if (!_enabled) return;
+
+            if (_running)
+            {
+                _sinceStart += deltaSeconds;
+                if (_sinceStart >= _nextFlashAt)
+                {
+                    // The interval runs FROM THIS FLASH, not from Start(). An absolute
+                    // deadline here made the gaps shrink every cycle (5s, then whatever
+                    // was left of the previous interval) and collapse toward zero.
+                    _nextFlashAt = _sinceStart + NextIntervalSeconds();
+                    BeginPresentation();
+                }
+            }
+
+            if (_elapsed < PresentationSeconds)
+            {
+                _elapsed += deltaSeconds;
+                if (_elapsed >= PresentationSeconds) _elapsed = PresentationSeconds;
+            }
+        }
+
+        Notify();
+    }
+
+    /// <summary>Invoked on the UI thread at the end of every tick with the frame that
+    /// tick produced (null when nothing is due) — the preview's repaint hook, so the
+    /// preview and the broadcast are driven by ONE clock.</summary>
+    public Action<VideoFrame?>? OnFrame { get; set; }
+
+    private void Notify()
+    {
+        var cb = OnFrame;
+        if (cb == null) return;
+        // Read OUTSIDE the state lock: the callback is arbitrary code and must never
+        // run while _gate is held.
+        var frame = Frame;
+        if (frame == null) { cb(null); return; }
+
+        if (Application.Current is { } app && !app.Dispatcher.CheckAccess())
+        {
+            // Off the UI thread (a test driving the clock). The frame's buffer is
+            // recycled, so hand the deferred copy its own pixels.
+            var copy = new byte[frame.BgraPixels.Length];
+            Buffer.BlockCopy(frame.BgraPixels, 0, copy, 0, copy.Length);
+            app.Dispatcher.BeginInvoke(() => cb(new VideoFrame(frame.Width, frame.Height, copy)));
+        }
+        else
+        {
+            cb(frame);
+        }
+    }
+
+    /// <summary>Force a presentation now — the "show me the flash" path and the test seam.</summary>
+    public void Show()
+    {
+        EnsureRaster();
+        lock (_gate)
+        {
+            if (!_enabled) return;
+            BeginPresentation();
+        }
+    }
+
+    private double NextIntervalSeconds()
+        => (IntervalFloorMs + _random.Next(IntervalJitterMs)) / 1000.0;
+
+    private void BeginPresentation()
+    {
+        if (_raster == null) return;
+        _buffer ??= new byte[MasterWidth * MasterHeight * 4];
+        // A new presentation can land anywhere, so the previous credit's pixels must go
+        // before this one is written or the old spot ghosts through the fade. One 8MB
+        // clear per presentation (not per tick) keeps that cheap.
+        Array.Clear(_buffer);
+        var spot = ComputePlacement(_raster.Width, _raster.Height, MasterWidth, MasterHeight, _random);
+        _atX = (int)spot.X;
+        _atY = (int)spot.Y;
+        _elapsed = 0;
+    }
+
+    /// <summary>
+    /// The credit for the output compositor and the preview: a master-space frame holding
+    /// the glowing text at this presentation's random spot, alpha-scaled to the current
+    /// point on the fade envelope. Null when idle, or unlicensed.
+    /// <para><b>The frame's pixel buffer is recycled across ticks</b> (only the text rect
+    /// is rewritten) and its <see cref="VideoFrame.Epoch"/> is bumped every read, so the
+    /// compositor's buffer-identity paste cache can never false-hit a stale credit.
+    /// Consumers blit synchronously — copy the pixels if you need to keep them.</para></summary>
+    public VideoFrame? Frame
+    {
+        get
+        {
+            lock (_gate)
+            {
+                if (!_enabled || _elapsed >= PresentationSeconds || _raster == null || _buffer == null)
+                    return null;
+                var opacity = OpacityAt(_elapsed);
+                if (opacity <= 0) return null;
+                Paint(_buffer, _raster, _atX, _atY, opacity);
+                return new VideoFrame(MasterWidth, MasterHeight, _buffer) { Epoch = ++_epoch };
+            }
+        }
+    }
+
+    /// <summary>Full → hold → empty. Public and static so the preview and the tests
+    /// agree with the renderer instead of re-deriving the curve.</summary>
+    public static double OpacityAt(double elapsedSeconds)
+    {
+        if (elapsedSeconds < 0 || elapsedSeconds >= PresentationSeconds) return 0;
+        if (elapsedSeconds < FadeInSeconds) return elapsedSeconds / FadeInSeconds;
+        if (elapsedSeconds < FadeInSeconds + HoldSeconds) return 1.0;
+        return 1.0 - ((elapsedSeconds - (FadeInSeconds + HoldSeconds)) / FadeOutSeconds);
+    }
+
+    /// <summary>
+    /// A random top-left offset that keeps the whole credit ON the canvas. The text is a
+    /// single pre-measured line, so it can never wrap — this is the "how far can the
+    /// left margin travel" limit the creator described: <c>0 … (canvas - creditWidth)</c>
+    /// horizontally, likewise vertically. Pure + static, so the rule is directly testable.
+    /// </summary>
+    public static Point ComputePlacement(int creditWidth, int creditHeight,
+        int canvasWidth, int canvasHeight, Random random)
+    {
+        var maxX = Math.Max(0, canvasWidth - creditWidth);
+        var maxY = Math.Max(0, canvasHeight - creditHeight);
+        return new Point(random.Next(0, maxX + 1), random.Next(0, maxY + 1));
+    }
+
+    /// <summary>Rewrite the credit rect into the master buffer with alpha scaled to
+    /// <paramref name="opacity"/>. The rect is fully overwritten each tick and the spot
+    /// is fixed for the whole presentation, so nothing stale accumulates and no clear
+    /// pass is needed here.</summary>
+    private static void Paint(byte[] buffer, VideoFrame raster, int atX, int atY, double opacity)
+    {
+        for (var y = 0; y < raster.Height; y++)
+        {
+            var dst = ((atY + y) * MasterWidth + atX) * 4;
+            var src = y * raster.Stride;
+            for (var x = 0; x < raster.Width; x++)
+            {
+                var a = raster.BgraPixels[src + x * 4 + 3];
+                if (a == 0) continue;
+                buffer[dst + x * 4] = raster.BgraPixels[src + x * 4];
+                buffer[dst + x * 4 + 1] = raster.BgraPixels[src + x * 4 + 1];
+                buffer[dst + x * 4 + 2] = raster.BgraPixels[src + x * 4 + 2];
+                buffer[dst + x * 4 + 3] = (byte)Math.Round(a * opacity);
+            }
+        }
+    }
+
+    /// <summary>Build the credit raster once, on the UI thread, and publish it under
+    /// the lock. Called from every clock entry point, so it is a no-op after the first.</summary>
+    private void EnsureRaster()
+    {
+        lock (_gate) { if (_raster != null) return; }
+        var raster = RenderNeonText(Text);
+        lock (_gate) { if (raster != null) { _raster = raster; } }
+    }
+
+    // ── rasterisation ──────────────────────────────────────────────────────────
+
+    /// <summary>
+    /// Rasterize the credit once, tight to the glyphs plus glow, on the UI thread (WPF
+    /// <c>RenderTargetBitmap</c>, Pbgra32→straight alpha exactly like
+    /// <see cref="AlertTickerRenderer"/>) and cached — this is per-text work, not
+    /// per-frame, so the pump can afford to run every tick at 30fps.
+    /// <para>The neon is a bright core plus a feathered halo: the glyphs redrawn at
+    /// shrinking radii with rising alpha, the two colours offset in opposite directions,
+    /// which is what makes it read as a lit tube rather than a drop shadow.</para></summary>
+    private static VideoFrame? RenderNeonText(string text)
+    {
+        if (Application.Current is { } app && !app.Dispatcher.CheckAccess())
+        {
+            VideoFrame? result = null;
+            app.Dispatcher.Invoke(() => result = RenderNeonText(text));
+            return result;
+        }
+
+        var font = new Typeface(new FontFamily("Segoe UI"), FontStyles.Normal,
+            FontWeights.Bold, FontStretches.Normal);
+        var probe = new FormattedText(text, CultureInfo.InvariantCulture,
+            FlowDirection.LeftToRight, font, FontSize, Brushes.White, 1.0);
+
+        var w = (int)Math.Ceiling(probe.Width) + (int)(GlowPadding * 2);
+        var h = (int)Math.Ceiling(probe.Height) + (int)(GlowPadding * 2);
+        if (w <= 0 || h <= 0) return null;
+
+        var visual = new DrawingVisual();
+        using (var dc = visual.RenderOpen())
+        {
+            // Three halo rings per colour. Wide+dim first, then progressively tighter and
+            // brighter, so the falloff is feathered instead of a hard-edged blob.
+            foreach (var (radius, alpha) in new[] { (30.0, 0.16), (20.0, 0.26), (11.0, 0.40) })
+            {
+                DrawHalo(dc, text, font, radius, alpha, NeonRed, +1);
+                DrawHalo(dc, text, font, radius, alpha, NeonBlue, -1);
+            }
+            // A tight white bloom hugging the glyphs sells the brightness of the tube.
+            DrawHalo(dc, text, font, 4.0, 0.55, CoreColor, +1);
+            // The core itself, sharp and opaque, drawn last.
+            dc.DrawText(new FormattedText(text, CultureInfo.InvariantCulture,
+                FlowDirection.LeftToRight, font, FontSize, new SolidColorBrush(CoreColor), 1.0),
+                new Point(GlowPadding, GlowPadding));
+        }
+
+        var bitmap = new RenderTargetBitmap(w, h, 96, 96, PixelFormats.Pbgra32);
+        bitmap.Render(visual);
+
+        var pixels = new byte[w * h * 4];
+        bitmap.CopyPixels(pixels, w * 4, 0);
+
+        // Pbgra32 is premultiplied — unpremultiply, or straight-alpha source-over in the
+        // compositor haloes the glyph edges.
+        for (var i = 0; i < pixels.Length; i += 4)
+        {
+            var a = pixels[i + 3];
+            if (a == 0 || a == 255) continue;
+            pixels[i] = (byte)(pixels[i] * 255 / a);
+            pixels[i + 1] = (byte)(pixels[i + 1] * 255 / a);
+            pixels[i + 2] = (byte)(pixels[i + 2] * 255 / a);
+        }
+        return new VideoFrame(w, h, pixels);
+    }
+
+    private static void DrawHalo(DrawingContext dc, string text, Typeface font,
+        double radius, double alpha, Color color, int direction)
+    {
+        var brush = new SolidColorBrush(color);
+        const int spokes = 12;
+        for (var i = 0; i < spokes; i++)
+        {
+            var angle = 2 * Math.PI * i / spokes;
+            brush.Opacity = alpha;
+            var ft = new FormattedText(text, CultureInfo.InvariantCulture,
+                FlowDirection.LeftToRight, font, FontSize, brush, 1.0);
+            dc.DrawText(ft, new Point(
+                GlowPadding + Math.Cos(angle) * radius * direction,
+                GlowPadding + Math.Sin(angle) * radius * direction));
+        }
+    }
+
+    public void Dispose() => _timer?.Stop();
+}

Services/Compositor/CompositeTimings.cs

@@ -0,0 +1,76 @@
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace ytLive.Services.Compositor;
+
+/// <summary>
+/// Per-stage composite timing (webcam-cadence unit, 2026-10-16): wall time per render
+/// pass, split into named stages — the backdrop, every element (keyed by z-index +
+/// name), the global overlays, and the final output scale. The pump owns one instance
+/// for the whole session, passes it into <see cref="SceneCompositor.Render"/> /
+/// <c>CompositeLayers</c> / <c>BakeStaticBase</c>, and logs an averaged breakdown every
+/// stats window — the "which of the 6 elements eats ~140ms" reading the old stats line
+/// could not give (it reported render/acquire/resolve, never the culprit layer).
+/// <para>Stage names are stable and greppable: <c>backdrop</c>, <c>base</c>,
+/// <c>flash</c>, <c>social</c>, <c>ticker</c>, <c>zoom</c>, <c>scale</c>,
+/// <c>bake backdrop</c>, <c>bake overlays</c>, and <c>#&lt;index&gt; &lt;name&gt;</c> per
+/// element (bake-pass elements are prefixed <c>bake</c> so a one-off rebake cannot
+/// masquerade as a per-composite cost). A <c>#&lt;i&gt; &lt;name&gt; raster</c> sub-stage NESTS inside its parent's total
+/// (it is the paste-cache rasterize miss — the prime suspect when one element costs a
+/// full resample every tick). Stage time INCLUDES that stage's frame resolve; resolve
+/// is separately totalled in the stats line.</para>
+/// <para>Single writer in production (the pump's render thread — every blit joins its
+/// <see cref="StripPool"/> workers before returning); the lock only makes a test able
+/// to share one across threads.</para>
+/// </summary>
+public sealed class CompositeTimings
+{
+    private readonly object _gate = new();
+    private readonly Dictionary<string, long> _stages = new(StringComparer.Ordinal);
+
+    /// <summary>Accumulate one stage sample. Non-positive ticks are dropped — a
+    /// skipped layer must not create a zero-cost entry that dilutes the reading.</summary>
+    public void Add(string stage, long ticks)
+    {
+        if (ticks <= 0 || stage.Length == 0) return;
+        lock (_gate)
+        {
+            _stages.TryGetValue(stage, out var cur);
+            _stages[stage] = cur + ticks;
+        }
+    }
+
+    /// <summary>Clear every stage — called once per stats window after the parts line
+    /// is logged, so each window reports its own breakdown.</summary>
+    public void Reset()
+    {
+        lock (_gate) _stages.Clear();
+    }
+
+    /// <summary>Average milliseconds per render for every stage at or above
+    /// <paramref name="minMs"/>, sorted slowest-first:
+    /// <c>"#2 Webcam 88.1ms, backdrop 61.2ms, #2 Webcam raster 84.0ms"</c>.
+    /// <paramref name="renders"/> is the divisor (the window's render count, so the
+    /// numbers compare directly with the stats line's <c>avg render</c>). The floor
+    /// keeps a healthy pipeline from burying the contender in zeroes; the empty string
+    /// means nothing was composited (the fully-static shortcut and C4 cache hits do no
+    /// per-element work — an empty parts line there is the correct reading).</summary>
+    public string Describe(int renders, double minMs = 0.1)
+    {
+        List<KeyValuePair<string, long>> snap;
+        lock (_gate)
+        {
+            if (_stages.Count == 0) return string.Empty;
+            snap = _stages.ToList();
+        }
+
+        var freq = (double)Stopwatch.Frequency;
+        var parts = snap
+            .Select(kv => (Stage: kv.Key, Ms: kv.Value / freq * 1000.0 / System.Math.Max(1, renders)))
+            .Where(p => p.Ms >= minMs)
+            .OrderByDescending(p => p.Ms)
+            .Select(p => $"{p.Stage} {p.Ms:F1}ms");
+        return string.Join(", ", parts);
+    }
+}

Services/Compositor/SceneCompositor.cs

@@ -1,3 +1,6 @@
+using System.Buffers;
+using System.Collections.Generic;
+using ytLive.Helpers;
 using ytLive.Models;
 
 namespace ytLive.Services.Compositor;
@@ -14,12 +17,32 @@ namespace ytLive.Services.Compositor;
 /// </summary>
 public sealed class SceneCompositor
 {
+    // Paste cache (take-8 fix, 2026-09-04): the Live scene re-sampled ~680k bilinear
+    // pixels EVERY tick even though only the camera actually changes at that rate —
+    // chat/web/image layers are identical frame after frame. Same shape as OBS (the
+    // source surface is cached, the compositor blits): a scaled/round-clipped/mirrored
+    // layer rasterizes once and is pasted (row-copy/blend) on every later tick.
+    // Keyed by the SOURCE FRAME IDENTITY (array + Epoch + CropBounds) — producers hand
+    // out fresh immutable byte[], or recycled-ring arrays whose monotonic Epoch distinguishes
+    // each generation (screen capture, take-11 fix). CropBounds must be in the key because
+    // the same frame (same Pixels/Epoch/Width/Height) can have different CropBounds as
+    // the element is resized — a stale cached raster with wrong crop pixels would corrupt
+    // the output. Bounds-checked eviction clears wholesale.
+    private sealed record PasteKey(byte[] Pixels, long Epoch, int SrcW, int SrcH, int DstW, int DstH, bool Round, bool Mirror, (int X, int Y, int W, int H)? CropBounds);
+    private static readonly Dictionary<PasteKey, VideoFrame> _pasteCache = new();
+    private static readonly Dictionary<SceneElement, VideoFrame> _elementRasters = new(ReferenceEqualityComparer.Instance);
+    private static readonly object _pasteGate = new();
+    private const int MaxPasteEntries = 256;
+
     /// <summary>
     /// Composite <paramref name="scene"/> into the tier's output frame. Layer order (back →
     /// front): live background (the scene's <c>IsBackground</c> source) → background image →
     /// visible elements (z-order = <c>Elements</c> order, mirroring the XAML DataTemplate) →
     /// branding flash → social bar (a global overlay; spans the master width at
-    /// <paramref name="socialBarTop"/>). Transparent regions read opaque black.
+    /// <paramref name="socialBarTop"/>) → stream-alert ticker (drawn INSIDE the Stream
+    /// Alerts box, at the origin the frame carries on <see cref="VideoFrame.Placement"/>;
+    /// creator ruling 2026-09-26 — it used to be a global bar pinned to the very top).
+    /// Transparent regions read opaque black.
     /// </summary>
     public VideoFrame Render(
         Scene scene,
@@ -27,7 +50,12 @@ public sealed class SceneCompositor
         VideoFrame? flashFrame,
         CompositorOptions options,
         VideoFrame? socialBarFrame = null,
-        int socialBarTop = 0)
+        int socialBarTop = 0,
+        VideoFrame? staticBase = null,
+        int split = -1,
+        byte[]? scratch = null,
+        VideoFrame? tickerFrame = null,
+        CompositeTimings? timings = null)
     {
         if (scene == null) throw new ArgumentNullException(nameof(scene));
         if (frameFor == null) throw new ArgumentNullException(nameof(frameFor));
@@ -39,14 +67,84 @@ public sealed class SceneCompositor
 
         var cropW = options.SourceRectWidth;
         var cropH = options.SourceRectHeight;
-        var buffer = new byte[cropW * cropH * 4];
-        for (var i = 3; i < buffer.Length; i += 4)
-            buffer[i] = 255; // opaque black base — video frames are never transparent
+        var buffer = scratch != null && scratch.Length == cropW * cropH * 4
+            ? scratch
+            : new byte[cropW * cropH * 4];
 
+        // staticBase != null: the caller pre-baked all static layers below `split`.
+        // We copy it (never mutate the cached base) and composite elements[split..] on top.
+        if (staticBase != null)
+        {
+            if (staticBase.Width != cropW || staticBase.Height != cropH)
+                throw new ArgumentException("The static base must match the source rect.", nameof(staticBase));
+            var tBase = System.Diagnostics.Stopwatch.GetTimestamp();
+            Buffer.BlockCopy(staticBase.BgraPixels, 0, buffer, 0, buffer.Length);
+            timings?.Add("base", System.Diagnostics.Stopwatch.GetTimestamp() - tBase);
+        }
+        else
+        {
+            if (split < 0) split = scene.Elements.Count;
+
+            var tBackdrop = System.Diagnostics.Stopwatch.GetTimestamp();
             var elements = scene.Elements;
-
             var liveCapture = elements.OfType<Source>().FirstOrDefault(s => s.IsBackground);
             var liveCaptureFrame = liveCapture != null && liveCapture.IsVisible ? frameFor(liveCapture) : null;
+
+            // A master-sized live backdrop paints every pixel of the base — the
+            // opaque-black pre-fill (2M byte writes) would be dead work. Capture
+            // frames are opaque BGRA by contract (the WinRT path ignores alpha),
+            // so the 1:1 row walk covers the full rect.
+            var covered = liveCaptureFrame != null
+                && liveCaptureFrame.Width == cropW && liveCaptureFrame.Height == cropH;
+            if (!covered)
+            {
+                if (liveCaptureFrame != null)
+                {
+                    var (uScale, uOx, uOy) = StretchMath.UniformToFill(cropW, cropH, liveCaptureFrame.Width, liveCaptureFrame.Height);
+                    var drawnW = liveCaptureFrame.Width * uScale;
+                    var drawnH = liveCaptureFrame.Height * uScale;
+                    var ox = (int)Math.Floor(uOx);
+                    var oy = (int)Math.Floor(uOy);
+                    var oh = (int)Math.Ceiling(oy + drawnH);
+                    var ow = cropW;
+                    if (oy > 0)
+                    {
+                        var topCount = oy * ow;
+                        for (var i = 3; i < topCount * 4; i += 4)
+                            buffer[i] = 255;
+                    }
+                    if (oh < cropH)
+                    {
+                        var start = oh * ow;
+                        var bottomCount = (cropH - oh) * ow;
+                        for (var i = start * 4 + 3; i < (start + bottomCount) * 4; i += 4)
+                            buffer[i] = 255;
+                    }
+                    if (ox > 0 || (int)Math.Ceiling(uOx + drawnW) < cropW)
+                    {
+                        var x0s = (int)Math.Floor(uOx);
+                        var x1s = (int)Math.Ceiling(uOx + drawnW);
+                        for (var y = oy; y < oh && y < cropH; y++)
+                        {
+                            var di = (y * ow + 0) * 4;
+                            for (var x = 0; x < x0s && x < ow; x++)
+                            {
+                                buffer[di + x * 4 + 3] = 255;
+                            }
+                            for (var x = x1s; x < ow; x++)
+                            {
+                                buffer[di + x * 4 + 3] = 255;
+                            }
+                        }
+                    }
+                }
+                else
+                {
+                    for (var i = 3; i < buffer.Length; i += 4)
+                        buffer[i] = 255; // opaque black base
+                }
+            }
+
             if (liveCaptureFrame != null)
                 BlitContent(buffer, cropW, cropH, 0, 0, cropW, cropH, liveCaptureFrame, 1f, false, false);
 
@@ -55,40 +153,345 @@ public sealed class SceneCompositor
             if (backgroundFrame != null)
                 BlitContent(buffer, cropW, cropH, 0, 0, cropW, cropH, backgroundFrame, 1f, false, false);
 
-        foreach (var element in elements)
+            timings?.Add("backdrop", System.Diagnostics.Stopwatch.GetTimestamp() - tBackdrop);
+
+            for (var ei = 0; ei < elements.Count; ei++)
             {
+                var element = elements[ei];
                 if (!element.IsVisible) continue;
                 switch (element)
                 {
                     case Source { IsBackground: true }:
                     case Source { Type: SourceType.Background }:
                     case Source { Type: SourceType.TextOverlay }:
-                    continue; // background/background are their own layers; Text isn't shipped
+                    case ZoomSceneElement { IsZoomActive: true }:
+                        continue;
+                }
+                var fullFrame = frameFor(element);
+                if (fullFrame == null) continue;
+                BlitBakedElement(buffer, cropW, cropH, options, element, fullFrame, timings, $"#{ei} {element.Name}");
+            }
         }
 
+        // Composite the above-split layers (dynamic + any static above them) per frame.
+        for (var i = Math.Max(0, split); i < scene.Elements.Count; i++)
+        {
+            var element = scene.Elements[i];
+            if (!element.IsVisible) continue;
+            switch (element)
+            {
+                case Source { IsBackground: true }:
+                case Source { Type: SourceType.Background }:
+                case Source { Type: SourceType.TextOverlay }:
+                case ZoomSceneElement { IsZoomActive: true }:
+                    continue;
+            }
             var frame = frameFor(element);
             if (frame == null) continue;
+            BlitBakedElement(buffer, cropW, cropH, options, element, frame, timings, $"#{i} {element.Name}");
+        }
 
+        if (flashFrame != null)
+        {
+            var tFlash = System.Diagnostics.Stopwatch.GetTimestamp();
+            BlitOverlay(buffer, cropW, cropH, options, flashFrame, 0, 0);
+            timings?.Add("flash", System.Diagnostics.Stopwatch.GetTimestamp() - tFlash);
+        }
+
+        if (socialBarFrame != null && socialBarFrame.Width > 0 && socialBarFrame.Height > 0)
+        {
+            var tSocial = System.Diagnostics.Stopwatch.GetTimestamp();
+            BlitOverlay(buffer, cropW, cropH, options, socialBarFrame, 0, socialBarTop);
+            timings?.Add("social", System.Diagnostics.Stopwatch.GetTimestamp() - tSocial);
+        }
+
+        if (tickerFrame != null && tickerFrame.Width > 0 && tickerFrame.Height > 0)
+        {
+            var tTicker = System.Diagnostics.Stopwatch.GetTimestamp();
+            BlitOverlay(buffer, cropW, cropH, options, tickerFrame, tickerFrame.OriginX, tickerFrame.OriginY);
+            timings?.Add("ticker", System.Diagnostics.Stopwatch.GetTimestamp() - tTicker);
+        }
+
+        // The zoom box is layer n+1: a live 2x view of a FIXED capture window sampled
+        // from the frame just composited (all layers). Drawn LAST — above everything.
+        // The box/2 capture is anchored at the click, so dragging the box only moves
+        // the box; the content it shows never changes (creator ruling 2026-10-08).
+        var zoom = scene.Elements.OfType<ZoomSceneElement>().FirstOrDefault(z => z.IsZoomActive);
+        if (zoom != null)
+        {
+            var tZoom = System.Diagnostics.Stopwatch.GetTimestamp();
+            BlitZoom(buffer, cropW, cropH, options, zoom);
+            timings?.Add("zoom", System.Diagnostics.Stopwatch.GetTimestamp() - tZoom);
+        }
+
+        var tScale = System.Diagnostics.Stopwatch.GetTimestamp();
+        var scaled = StretchMath.BilinearScale(
+            new VideoFrame(cropW, cropH, buffer), options.OutputWidth, options.OutputHeight);
+        timings?.Add("scale", System.Diagnostics.Stopwatch.GetTimestamp() - tScale);
+        return scaled;
+    }
+
+    /// <summary>
+    /// Render the static base of a scene: the opaque black layer, the live-capture
+    /// background, the background image, and every <paramref name="split"/> z-layers
+    /// below the split point (all of which are static by construction — see
+    /// <see cref="SceneElement.Kind"/>). The result is a source-rect sized frame that
+    /// <see cref="Render"/> can start from and composite the dynamic/above-split layers
+    /// onto each tick. Returns null when there is no static layer at all.
+    /// </summary>
+    public static VideoFrame? BakeStaticBase(
+        Scene scene,
+        int split,
+        Func<SceneElement, VideoFrame?> frameFor,
+        Func<CompositorOptions> options,
+        VideoFrame? socialBarFrame = null,
+        int socialBarTop = 0,
+        VideoFrame? flashFrame = null,
+        CompositeTimings? timings = null)
+    {
+        if (split <= 0) return null;
+        var opts = options();
+        if (opts.SourceRectWidth <= 0 || opts.SourceRectHeight <= 0) return null;
+
+        var tBake = System.Diagnostics.Stopwatch.GetTimestamp();
+        var cropW = opts.SourceRectWidth;
+        var cropH = opts.SourceRectHeight;
+        var buffer = new byte[cropW * cropH * 4];
+        for (var i = 3; i < buffer.Length; i += 4)
+            buffer[i] = 255;
+
+        var elements = scene.Elements;
+
+        var liveCapture = elements.OfType<Source>().FirstOrDefault(s => s.IsBackground);
+        if (liveCapture != null)
+        {
+            var liveCaptureFrame = liveCapture.IsVisible ? frameFor(liveCapture) : null;
+            if (liveCaptureFrame != null && split > elements.IndexOf(liveCapture))
+                BlitContent(buffer, cropW, cropH, 0, 0, cropW, cropH, liveCaptureFrame, 1f, false, false);
+        }
+
+        var background = elements.OfType<Source>().FirstOrDefault(s => s.Type == SourceType.Background);
+        if (background != null)
+        {
+            var backgroundFrame = frameFor(background);
+            if (backgroundFrame != null && split > elements.IndexOf(background))
+                BlitContent(buffer, cropW, cropH, 0, 0, cropW, cropH, backgroundFrame, 1f, false, false);
+        }
+
+        timings?.Add("bake backdrop", System.Diagnostics.Stopwatch.GetTimestamp() - tBake);
+
+        for (var i = 0; i < split; i++)
+        {
+            var element = scene.Elements[i];
+            if (!element.IsVisible) continue;
+            switch (element)
+            {
+                case Source { IsBackground: true }:
+                case Source { Type: SourceType.Background }:
+                case Source { Type: SourceType.TextOverlay }:
+                case ZoomSceneElement:
+                    continue;
+            }
+            var frame = frameFor(element);
+            if (frame == null) continue;
+            BlitBakedElement(buffer, cropW, cropH, opts, element, frame, timings, $"bake #{i} {element.Name}");
+        }
+
+        var baked = new VideoFrame(cropW, cropH, buffer);
+        if (flashFrame != null || (socialBarFrame != null && socialBarFrame.Width > 0 && socialBarFrame.Height > 0))
+        {
+            var tOverlays = System.Diagnostics.Stopwatch.GetTimestamp();
+            if (flashFrame != null)
+                baked = Overlay(baked, opts, flashFrame, 0, 0);
+            if (socialBarFrame != null && socialBarFrame.Width > 0 && socialBarFrame.Height > 0)
+                baked = Overlay(baked, opts, socialBarFrame, 0, socialBarTop);
+            timings?.Add("bake overlays", System.Diagnostics.Stopwatch.GetTimestamp() - tOverlays);
+        }
+        return baked;
+    }
+
+    /// <summary>The compositor's dynamic/above-split path: start from an existing frame
+    /// buffer and composite the z-layers from <paramref name="split"/> onward on top.
+    /// When <paramref name="baseFrame"/> is null the caller must fall back to full render.
+    /// The social bar never reaches here (it IS baked into the static base) but the alert
+    /// ticker must: it is dynamic by construction — only ever present while an alert plays —
+    /// so it overlays LAST, pinned to the very top (TASK 47).</summary>
+    public static VideoFrame CompositeLayers(
+        VideoFrame baseFrame,
+        Scene scene,
+        int split,
+        Func<SceneElement, VideoFrame?> frameFor,
+        CompositorOptions options,
+        VideoFrame? socialBarFrame = null,
+        int socialBarTop = 0,
+        VideoFrame? flashFrame = null,
+        byte[]? scratch = null,
+        VideoFrame? tickerFrame = null,
+        CompositeTimings? timings = null)
+    {
+        var cropW = options.SourceRectWidth;
+        var cropH = options.SourceRectHeight;
+        // We must not mutate the cached base: copy it into a fresh (or pooled) buffer.
+        var buffer = scratch != null && scratch.Length == baseFrame.BgraPixels.Length
+            ? scratch
+            : new byte[baseFrame.BgraPixels.Length];
+        var tBase = System.Diagnostics.Stopwatch.GetTimestamp();
+        Buffer.BlockCopy(baseFrame.BgraPixels, 0, buffer, 0, baseFrame.BgraPixels.Length);
+        timings?.Add("base", System.Diagnostics.Stopwatch.GetTimestamp() - tBase);
+
+        for (var i = split; i < scene.Elements.Count; i++)
+        {
+            var element = scene.Elements[i];
+            if (!element.IsVisible) continue;
+            switch (element)
+            {
+                case Source { IsBackground: true }:
+                case Source { Type: SourceType.Background }:
+                case Source { Type: SourceType.TextOverlay }:
+                case ZoomSceneElement { IsZoomActive: true }:
+                    continue;
+            }
+            var frame = frameFor(element);
+            if (frame == null) continue;
+            BlitBakedElement(buffer, cropW, cropH, options, element, frame, timings, $"#{i} {element.Name}");
+        }
+
+        if (tickerFrame != null && tickerFrame.Width > 0 && tickerFrame.Height > 0)
+        {
+            var tTicker = System.Diagnostics.Stopwatch.GetTimestamp();
+            BlitOverlay(buffer, cropW, cropH, options, tickerFrame, tickerFrame.OriginX, tickerFrame.OriginY);
+            timings?.Add("ticker", System.Diagnostics.Stopwatch.GetTimestamp() - tTicker);
+        }
+
+        var zoom = scene.Elements.OfType<ZoomSceneElement>().FirstOrDefault(z => z.IsZoomActive);
+        if (zoom != null)
+        {
+            var tZoom = System.Diagnostics.Stopwatch.GetTimestamp();
+            BlitZoom(buffer, cropW, cropH, options, zoom);
+            timings?.Add("zoom", System.Diagnostics.Stopwatch.GetTimestamp() - tZoom);
+        }
+
+        var tScale = System.Diagnostics.Stopwatch.GetTimestamp();
+        var scaled = StretchMath.BilinearScale(new VideoFrame(cropW, cropH, buffer), options.OutputWidth, options.OutputHeight);
+        timings?.Add("scale", System.Diagnostics.Stopwatch.GetTimestamp() - tScale);
+        return scaled;
+    }
+
+    private static void BlitBakedElement(
+        byte[] buffer, int cropW, int cropH, CompositorOptions options, SceneElement element, VideoFrame frame,
+        CompositeTimings? timings, string stage)
+    {
+        var tElement = System.Diagnostics.Stopwatch.GetTimestamp();
         var ex = (float)(element.X - options.SourceRectX);
         var ey = (float)(element.Y - options.SourceRectY);
         var ew = (float)element.Width;
         var eh = (float)element.Height;
         var isRound = element.ClipShape == ClipShape.Round;
 
-            BlitContent(buffer, cropW, cropH, ex, ey, ew, eh, frame,
-                (float)element.Opacity, isRound, element.IsMirrored);
+        // All rect-placed elements route through the paste cache (take-9 lesson): the
+        // IsOpaque bypass kept re-sampling the webcam (~156k px) EVERY tick even when
+        // the device frame had not changed; an opaque source rasterizes to an opaque
+        // raster whose paste is a per-pixel copy branch, so hits beat the sampler and
+        // misses cost exactly what the bypass cost.
+        BlitCachedLayer(buffer, cropW, cropH, ex, ey, ew, eh, frame, element, isRound, timings, stage);
         if (element.HasBorder)
             DrawBorder(buffer, cropW, cropH, ex, ey, ew, eh, element, isRound);
+        timings?.Add(stage, System.Diagnostics.Stopwatch.GetTimestamp() - tElement);
     }
 
-        if (flashFrame != null)
-            BlitOverlay(buffer, cropW, cropH, options, flashFrame, 0, 0);
+    /// <summary>Non-opaque layer blit through the paste cache: the element-space raster
+    /// (scaled to the element rect, round-clipped, mirrored) depends only on the source
+    /// frame + rect + shape/mirror — NOT on position or opacity. Static content (chat,
+    /// web overlays, images, the media frame between updates) is sampled ONCE and pasted
+    /// at integer position with per-tixel blend; only layers whose source frame actually
+    /// changed (webcam at device fps) pay resampling.</summary>
+    private static void BlitCachedLayer(
+        byte[] buffer, int cropW, int cropH,
+        float ex, float ey, float ew, float eh,
+        VideoFrame frame, SceneElement element, bool isRound,
+        CompositeTimings? timings, string stage)
+    {
+        if (ew <= 0 || eh <= 0) return;
+        var dw = (int)System.Math.Ceiling(ew);
+        var dh = (int)System.Math.Ceiling(eh);
+        if (dw <= 0 || dh <= 0) return;
+        var mirror = element.IsMirrored;
 
-        if (socialBarFrame != null && socialBarFrame.Width > 0 && socialBarFrame.Height > 0)
-            BlitOverlay(buffer, cropW, cropH, options, socialBarFrame, 0, socialBarTop);
+        PasteKey? key = null;
+        VideoFrame? raster = null;
+        lock (_pasteGate)
+        {
+            key = new PasteKey(frame.BgraPixels, frame.Epoch, frame.Width, frame.Height, dw, dh, isRound, mirror, frame.CropBounds);
+            _pasteCache.TryGetValue(key, out raster);
+        }
 
-        return StretchMath.BilinearScale(
-            new VideoFrame(cropW, cropH, buffer), options.OutputWidth, options.OutputHeight);
+        if (raster == null)
+        {
+            var tRaster = System.Diagnostics.Stopwatch.GetTimestamp();
+            // Rasterize in ELEMENT space on a TRANSPARENT base: the sampler writes 255
+            // alpha only where it actually draws, so untouched margins (outside the
+            // round clip, past the UniformToFill edges) stay alpha 0 and the paste
+            // reveals the master beneath instead of black. The ARRAY is reused per
+            // element (see _elementRasters note) — new source generations re-raster
+            // in place, so the steady state allocates nothing.
+            lock (_pasteGate)
+            {
+                if (_elementRasters.TryGetValue(element, out var existing)
+                    && existing.Width == dw && existing.Height == dh)
+                    raster = existing;
+            }
+            if (raster == null) raster = new VideoFrame(dw, dh, new byte[dw * dh * 4]);
+            Array.Clear(raster.BgraPixels);
+            BlitContentRaw(raster.BgraPixels, dw, dh, 0, 0, ew, eh, frame, 1f, isRound, mirror, transparentDst: true);
+            lock (_pasteGate)
+            {
+                // Only the SOURCE frame's identity is a real key owner; drop any older
+                // entry that shared this element's reused raster so a stale key can never
+                // paste a mid-update array.
+                if (_pasteCache.Count >= MaxPasteEntries) _pasteCache.Clear();
+                _pasteCache[key!] = raster;
+                _elementRasters[element] = raster;
+            }
+            timings?.Add(stage + " raster", System.Diagnostics.Stopwatch.GetTimestamp() - tRaster);
+        }
+
+        // Paste at integer position; opacity blends. The raster is never flagged
+        // IsOpaque — round clips/margins carry alpha 0 — so the row blend always runs.
+        var op = (int)(System.Math.Clamp(element.Opacity, 0f, 1f) * 256);
+        if (op <= 0) return;
+        var px = (int)System.Math.Floor(ex);
+        var py = (int)System.Math.Floor(ey);
+        var x0 = System.Math.Max(0, px);
+        var y0 = System.Math.Max(0, py);
+        var x1 = System.Math.Min(cropW, px + dw);
+        var y1 = System.Math.Min(cropH, py + dh);
+        if (x0 >= x1 || y0 >= y1) return;
+        var s = raster.BgraPixels;
+        StripPool.For(y0, y1, y =>
+        {
+            var si = ((y - py) * dw + (x0 - px)) * 4;
+            var len = x1 - x0;
+            if (op == 256)
+                BlendRowOpaque(buffer, (y * cropW + x0) * 4, s, si, len);
+            else
+                BlendRowWeighted(buffer, (y * cropW + x0) * 4, s, si, len, op);
+        });
+    }
+
+    /// <summary>Copy <paramref name="frame"/> and blit a global overlay onto the copy
+    /// at (sx0, sy0) in crop space. internal (not private) because the frame pump's
+    /// fully-static path needs it: that path stretches the cached bake straight to the
+    /// output, so any per-frame overlay — social bar, alert ticker, brand flash — has to
+    /// be composited here first. Copying is the whole point: the bake is cached, and a
+    /// flash written straight into it would freeze there and never expire.</summary>
+    internal static VideoFrame Overlay(VideoFrame frame, CompositorOptions options, VideoFrame overlay, int sx0, int sy0)
+    {
+        var cropW = options.SourceRectWidth;
+        var cropH = options.SourceRectHeight;
+        var buffer = new byte[frame.BgraPixels.Length];
+        Buffer.BlockCopy(frame.BgraPixels, 0, buffer, 0, buffer.Length);
+        BlitOverlay(buffer, cropW, cropH, options, overlay, sx0, sy0);
+        return new VideoFrame(cropW, cropH, buffer);
     }
 
     /// <summary>
@@ -131,26 +534,144 @@ public sealed class SceneCompositor
     {
         if (ew <= 0 || eh <= 0) return;
 
+        var (scale, ox, oy) = StretchMath.UniformToFill(ew, eh, src.Width, src.Height);
+
+        // 1:1 aligned fast path (the full-frame backdrop, master-sized overlays):
+        // bilinear sampling at scale 1 with integer offsets is the identity, so the
+        // blit is a row walk, not 2M float samples + rounds. Research-first (2026-09-03,
+        // take-3 fix; libyuv's row-based BLEND_NONE pattern —
+        // https://chromium.googlesource.com/libyuv/libyuv/): the 258ms/frame render
+        // that time-lapsed take 3 lived in the general loop below.
+        if (!isRound && !isMirror && scale == 1f && ox == 0f && oy == 0f
+            && ex == MathF.Floor(ex) && ey == MathF.Floor(ey))
+        {
+            Blit1To1Rows(dst, dstW, dstH, (int)ex, (int)ey, src, opacity);
+            return;
+        }
+
+        BlitContentRaw(dst, dstW, dstH, ex, ey, ew, eh, src, opacity, isRound, isMirror);
+    }
+
+    /// <summary>The general scaled/clipped/mirrored sampler (integer fixed-point
+    /// bilinear + source-over). Also rasterizes paste-cache entries in ELEMENT space
+    /// onto a TRANSPARENT base (alpha 0) so pasting over the master keeps the round
+    /// clip and transparency of the untouched margins.</summary>
+    private static void BlitContentRaw(
+        byte[] dst, int dstW, int dstH,
+        float ex, float ey, float ew, float eh,
+        VideoFrame src, float opacity, bool isRound, bool isMirror,
+        bool transparentDst = false)
+    {
+        if (ew <= 0 || eh <= 0) return;
+
+        float scale, ox, oy, invScale;
+        float drawnW, drawnH;
+        // No CropBounds means "the whole source canvas is the crop region" — cbW/cbH
+        // MUST default to the full source dims, not 0. A zero cbW/cbH makes every
+        // sxCrop/syCrop below evaluate to 0 regardless of position, collapsing the
+        // entire sampled rect to source pixel (0,0) (the webcam gray-block regression,
+        // 2026-09-12: introduced by the CropBounds Fill-style scaling work the same
+        // day — CropBounds-bearing sources, i.e. the web widget, were never affected).
+        var cbX = 0;
+        var cbY = 0;
+        var cbW = src.Width;
+        var cbH = src.Height;
+
+        if (src.CropBounds is { } cb)
+        {
+            cbX = cb.X;
+            cbY = cb.Y;
+            cbW = cb.W;
+            cbH = cb.H;
+            scale = Math.Max(ew / cbW, eh / cbH);
+            invScale = 1f / scale;
+            drawnW = cbW * scale;
+            drawnH = cbH * scale;
+            ox = (ew - drawnW) / 2f;
+            oy = (eh - drawnH) / 2f;
+        }
+        else
+        {
+            var (uScale, uOx, uOy) = StretchMath.UniformToFill(ew, eh, src.Width, src.Height);
+            scale = uScale;
+            invScale = 1f / uScale;
+            ox = uOx;
+            oy = uOy;
+            drawnW = src.Width * uScale;
+            drawnH = src.Height * uScale;
+        }
+
+        var radius = Math.Min(ew, eh) / 2f;
+        var cx = ew / 2f;
+        var cy = eh / 2f;
+
         var x0 = Math.Max(0, (int)Math.Floor(ex));
         var y0 = Math.Max(0, (int)Math.Floor(ey));
         var x1 = Math.Min(dstW - 1, (int)Math.Ceiling(ex + ew));
         var y1 = Math.Min(dstH - 1, (int)Math.Ceiling(ey + eh));
         if (x0 > x1 || y0 > y1) return;
 
-        var (scale, ox, oy) = StretchMath.UniformToFill(ew, eh, src.Width, src.Height);
-        var drawnW = src.Width * scale;
-        var drawnH = src.Height * scale;
-        var radius = Math.Min(ew, eh) / 2f;
-        var cx = ew / 2f;
-        var cy = eh / 2f;
+        var op = (int)(Math.Clamp(opacity, 0f, 1f) * 256);
+        if (op <= 0) return;
+        var s = src.BgraPixels;
+        var srcStride = src.Width; // canvas stride in pixels (not bytes)
 
-        for (var y = y0; y <= y1; y++)
+        // Build horizontal LUT for scaled blit to reduce per-pixel divides. The table is
+        // READ by the strip workers while it is being sampled, so it must not be shared
+        // mutable state: it comes from the thread-safe ArrayPool and goes back in a finally
+        // (the static single-buffer version raced the moment the strips went parallel).
+        var lutCount = x1 - x0 + 1;
+        var sxLut = ArrayPool<float>.Shared.Rent(lutCount);
+        try
         {
-            for (var x = x0; x <= x1; x++)
+            var pxBase = x0 - ex;
+            for (var xi = 0; xi < lutCount; xi++)
+            {
+                var px = pxBase + xi;
+                float sxCanvas;
+                if (px < ox || px > ox + drawnW)
+                {
+                    sxCanvas = float.NaN;
+                }
+                else
+                {
+                    var sxNorm = (px - ox) / drawnW;
+                    sxNorm = sxNorm < 0f ? 0f : sxNorm > 1f ? 1f : sxNorm;
+                    var sxCrop = sxNorm * cbW;
+                    sxCanvas = cbX + sxCrop;
+                    if (sxCanvas < 0f) sxCanvas = 0f;
+                    if (sxCanvas > src.Width - 1f) sxCanvas = src.Width - 1f;
+                    if (isMirror) sxCanvas = src.Width - 1f - sxCanvas;
+                }
+                sxLut[xi] = sxCanvas;
+            }
+
+            StripPool.For(y0, y1 + 1, y =>
         {
-                var px = x - ex; // element space
             var py = y - ey;
-                if (px < ox || px > ox + drawnW || py < oy || py > oy + drawnH) continue;
+            if (py < oy || py > oy + drawnH) return;
+
+            // syNorm: normalized [0,1] position within the drawn content (vertically)
+            var syNorm = (py - oy) / drawnH;
+            if (syNorm < 0f) syNorm = 0f;
+            if (syNorm > 1f) syNorm = 1f;
+            // syCrop: pixel position within the crop region
+            var syCrop = syNorm * cbH;
+            // syCanvas: canvas pixel row (for buffer indexing)
+            var syCanvas = cbY + syCrop;
+            if (syCanvas < 0f) syCanvas = 0f;
+            if (syCanvas > src.Height - 1f) syCanvas = src.Height - 1f;
+            var syi = (int)syCanvas;
+            var sy1i = Math.Min(syi + 1, src.Height - 1);
+            var fy8 = (int)((syCanvas - syi) * 256);
+            var fyInv = 256 - fy8;
+
+            var di = (y * dstW + x0) * 4;
+            for (var xi = 0; xi < lutCount; xi++, di += 4)
+            {
+                var sxCanvas = sxLut[xi];
+                if (float.IsNaN(sxCanvas)) continue;
+                var px = pxBase + xi;
                 if (isRound)
                 {
                     var dx = px - cx;
@@ -158,12 +679,176 @@ public sealed class SceneCompositor
                     if (dx * dx + dy * dy > radius * radius) continue;
                 }
 
-                var sx = (px - ox) / scale;
-                var sy = (py - oy) / scale;
-                if (isMirror) sx = src.Width - 1 - sx;
-                var sample = StretchMath.SampleBgra(src.BgraPixels, src.Width, src.Height, sx, sy);
-                BlendPixel(dst, (y * dstW + x) * 4, sample, opacity);
+                var sxi = (int)sxCanvas;
+                var sx1i = Math.Min(sxi + 1, src.Width - 1);
+                var fx8 = (int)((sxCanvas - sxi) * 256);
+                var fxInv = 256 - fx8;
+
+                // ALL pixel indexing uses srcStride (canvas stride), NOT crop width
+                var p00 = (syi * srcStride + sxi) * 4;
+                var p10 = (syi * srcStride + sx1i) * 4;
+                var p01 = (sy1i * srcStride + sxi) * 4;
+                var p11 = (sy1i * srcStride + sx1i) * 4;
+                var sb = Bilinear(s[p00], s[p10], s[p01], s[p11], fx8, fxInv, fy8, fyInv);
+                var sg = Bilinear(s[p00 + 1], s[p10 + 1], s[p01 + 1], s[p11 + 1], fx8, fxInv, fy8, fyInv);
+                var sr = Bilinear(s[p00 + 2], s[p10 + 2], s[p01 + 2], s[p11 + 2], fx8, fxInv, fy8, fyInv);
+                var saFull = Bilinear(s[p00 + 3], s[p10 + 3], s[p01 + 3], s[p11 + 3], fx8, fxInv, fy8, fyInv);
+
+                var sa = saFull * op >> 8;
+                if (sa >= 255)
+                {
+                    dst[di] = (byte)sb;
+                    dst[di + 1] = (byte)sg;
+                    dst[di + 2] = (byte)sr;
+                    dst[di + 3] = 255;
                 }
+                else if (sa > 0)
+                {
+                    if (transparentDst)
+                    {
+                        // Element-raster pass on a TRANSPARENT base (the paste cache):
+                        // keep straight color + straight alpha so the paste rows can
+                        // source-over onto the opaque master. Premultiplying here (the
+                        // opaque-dst blend) stamped alpha 255 onto already-alpha-scaled
+                        // color — the paste over-wrote the scene with darkened ink, the
+                        // web widget's "black box" in recordings.
+                        dst[di] = (byte)sb;
+                        dst[di + 1] = (byte)sg;
+                        dst[di + 2] = (byte)sr;
+                        dst[di + 3] = (byte)sa;
+                    }
+                    else
+                    {
+                        var inv = 255 - sa;
+                        dst[di] = (byte)((sb * sa + dst[di] * inv + 127) / 255);
+                        dst[di + 1] = (byte)((sg * sa + dst[di + 1] * inv + 127) / 255);
+                        dst[di + 2] = (byte)((sr * sa + dst[di + 2] * inv + 127) / 255);
+                        dst[di + 3] = 255;
+                    }
+                }
+            }
+            });
+        }
+        finally
+        {
+            ArrayPool<float>.Shared.Return(sxLut);
+        }
+    }
+
+    /// <summary>Two-stage bilinear in 8.8 fixed point; result within ±1 of the
+    /// float StretchMath.SampleBgra (well inside every pixel test's ±2 tolerance).
+    /// The first stage must NOT shift back to 8 bits — shifting twice collapsed
+    /// every solid-255 sample to 1 (green overwrites silently degraded to no-ops;
+    /// caught by the SceneCompositor/SceneGraph pixel probes 2026-09-04).</summary>
+    private static int Bilinear(int tl, int tr, int bl, int br, int fx8, int fxInv, int fy8, int fyInv)
+    {
+        // Both stages in one 16.8 scale: top/bot ≤ 65280, ×256 + round ≤ 16.8M — int-safe.
+        var top = tl * fxInv + tr * fx8;
+        var bot = bl * fxInv + br * fx8;
+        return (top * fyInv + bot * fy8 + 32768) >> 16;
+    }
+
+    /// <summary>Row walk for a 1:1 aligned blit at integer offset (ex, ey): per-pixel
+    /// branch on source alpha — opaque rows copy straight, transparent pixels are
+    /// skipped, partial alpha blends in integer fixed-point (libyuv's pattern). The
+    /// master buffer's destination alpha is always opaque (black base paints 255 and
+    /// every blend writes 255), so dst alpha is never read — matching BlendPixel's
+    /// source-over result for opaque dst within ±1.</summary>
+    private static void Blit1To1Rows(byte[] dst, int dstW, int dstH, int ex, int ey, VideoFrame src, float opacity)
+    {
+        var op = (int)(Math.Clamp(opacity, 0f, 1f) * 256);
+        if (op <= 0) return;
+
+        var x0 = Math.Max(0, ex);
+        var y0 = Math.Max(0, ey);
+        var x1 = Math.Min(dstW, ex + src.Width);
+        var y1 = Math.Min(dstH, ey + src.Height);
+        if (x0 >= x1 || y0 >= y1) return;
+
+        // The take-4 fix: a full-canvas opaque capture (the Live backdrop) is ONE
+        // memcpy, not 2.07M managed loop iterations — the row walk below still cost
+        // ~58ms/frame dominated by bounds-check arithmetic and GC of the per-pixel
+        // loop's slowness, i.e. the same starvation shape as take 3, one floor lower.
+        if (op == 256 && src.IsOpaque && x0 == 0 && y0 == 0 && x1 == dstW && y1 == dstH)
+        {
+            Buffer.BlockCopy(src.BgraPixels, 0, dst, 0, dstW * dstH * 4);
+            return;
+        }
+        // Opaque source with 1:1 aligned region covering full canvas
+        if (op == 256 && src.IsOpaque && ex == 0 && ey == 0 && src.Width == dstW && src.Height == dstH)
+        {
+            Buffer.BlockCopy(src.BgraPixels, 0, dst, 0, dstW * dstH * 4);
+            return;
+        }
+
+        var d = dst.AsSpan();
+        var s = src.BgraPixels.AsSpan();
+        var rowLen = x1 - x0;
+        if (op == 256)
+        {
+            for (var y = y0; y < y1; y++)
+            {
+                var si = ((y - ey) * src.Width + (x0 - ex)) * 4;
+                BlendRowOpaque(d, (y * dstW + x0) * 4, s, si, rowLen);
+            }
+        }
+        else
+        {
+            for (var y = y0; y < y1; y++)
+            {
+                var si = ((y - ey) * src.Width + (x0 - ex)) * 4;
+                BlendRowWeighted(d, (y * dstW + x0) * 4, s, si, rowLen, op);
+            }
+        }
+    }
+
+    private static void BlendRowOpaque(Span<byte> dst, int di, ReadOnlySpan<byte> src, int si, int count)
+    {
+        for (var n = 0; n < count; n++)
+        {
+            var a = src[si + 3];
+            if (a == 255)
+            {
+                dst[di] = src[si];
+                dst[di + 1] = src[si + 1];
+                dst[di + 2] = src[si + 2];
+                dst[di + 3] = 255;
+            }
+            else if (a != 0)
+            {
+                var inv = 255 - a;
+                dst[di] = (byte)((src[si] * a + dst[di] * inv + 127) / 255);
+                dst[di + 1] = (byte)((src[si + 1] * a + dst[di + 1] * inv + 127) / 255);
+                dst[di + 2] = (byte)((src[si + 2] * a + dst[di + 2] * inv + 127) / 255);
+                dst[di + 3] = 255;
+            }
+            si += 4;
+            di += 4;
+        }
+    }
+
+    private static void BlendRowWeighted(Span<byte> dst, int di, ReadOnlySpan<byte> src, int si, int count, int op)
+    {
+        for (var n = 0; n < count; n++)
+        {
+            var a = src[si + 3] * op >> 8;
+            if (a >= 255)
+            {
+                dst[di] = src[si];
+                dst[di + 1] = src[si + 1];
+                dst[di + 2] = src[si + 2];
+                dst[di + 3] = 255;
+            }
+            else if (a > 0)
+            {
+                var inv = 255 - a;
+                dst[di] = (byte)((src[si] * a + dst[di] * inv + 127) / 255);
+                dst[di + 1] = (byte)((src[si + 1] * a + dst[di + 1] * inv + 127) / 255);
+                dst[di + 2] = (byte)((src[si + 2] * a + dst[di + 2] * inv + 127) / 255);
+                dst[di + 3] = 255;
+            }
+            si += 4;
+            di += 4;
         }
     }
 
@@ -201,22 +886,40 @@ public sealed class SceneCompositor
     }
 
     /// <summary>1:1 copy of a master-sized overlay (flash, social bar) cropped to the
-    /// active source rect. The overlay is positioned in master space by (sx0, sy0).</summary>
+    /// active source rect. The overlay is positioned in master space by (sx0, sy0).
+    /// Iterates only the intersection rect — the old loop walked every destination
+    /// pixel to blit a ~64px strip (2M iterations of bounds checks per overlay).</summary>
     private static void BlitOverlay(
         byte[] dst, int dstW, int dstH, CompositorOptions options,
         VideoFrame overlay, int sx0, int sy0)
     {
-        for (var y = 0; y < dstH; y++)
+        var dx0 = Math.Max(0, sx0 - options.SourceRectX);
+        var dy0 = Math.Max(0, sy0 - options.SourceRectY);
+        var dx1 = Math.Min(dstW, sx0 - options.SourceRectX + overlay.Width);
+        var dy1 = Math.Min(dstH, sy0 - options.SourceRectY + overlay.Height);
+        StripPool.For(dy0, dy1, y =>
         {
-            for (var x = 0; x < dstW; x++)
+            var si = ((y + options.SourceRectY - sy0) * overlay.Width
+                + dx0 + options.SourceRectX - sx0) * 4;
+            BlendRowOpaque(dst, (y * dstW + dx0) * 4, overlay.BgraPixels, si, dx1 - dx0);
+        });
+    }
+
+    /// <summary>
+    /// The zoom box layer (n+1): map the element's master-space box and capture to
+    /// crop space and 2x-magnify the capture onto the box from the composed frame.
+    /// The active zoom element is never blitted by the normal layer loops — the
+    /// switch skips it and this pass draws it above everything, last.
+    /// </summary>
+    private static void BlitZoom(
+        byte[] dst, int cropW, int cropH, CompositorOptions options, ZoomSceneElement zoom)
     {
-                var sx = x + options.SourceRectX - sx0;
-                var sy = y + options.SourceRectY - sy0;
-                if (sx < 0 || sy < 0 || sx >= overlay.Width || sy >= overlay.Height) continue;
-                var sample = StretchMath.SampleBgra(overlay.BgraPixels, overlay.Width, overlay.Height, sx, sy);
-                BlendPixel(dst, (y * dstW + x) * 4, sample, 1f);
-            }
-        }
+        ZoomMagnifier.MagnifyInto(
+            dst, cropW, cropH,
+            zoom.X - options.SourceRectX, zoom.Y - options.SourceRectY,
+            zoom.Width, zoom.Height,
+            zoom.CaptureX - options.SourceRectX, zoom.CaptureY - options.SourceRectY,
+            zoom.ClipShape == ClipShape.Round);
     }
 
     /// <summary>Straight-alpha source-over blend; the frame's alpha (and the layer opacity) drives coverage.</summary>

Services/Compositor/StaticPixelCache.cs

@@ -16,6 +16,10 @@ public static class StaticPixelCache
     public static VideoFrame? Get(string assetId)
     {
         if (string.IsNullOrWhiteSpace(assetId)) return null;
+        // Locked: the frame pump decodes from its own thread now (take-8 off-UI fix),
+        // so the dictionary genuinely races with UI-path callers (snapshots, heals).
+        lock (Cache)
+        {
             if (Cache.TryGetValue(assetId, out var frame)) return frame;
 
             var bytes = LayoutStore.Instance?.GetAssetBytes(assetId);
@@ -25,6 +29,7 @@ public static class StaticPixelCache
             if (decoded != null) Cache[assetId] = decoded;
             return decoded;
         }
+    }
 
     public static VideoFrame? Decode(byte[] bytes)
     {

Services/Compositor/ZoomMagnifier.cs

@@ -0,0 +1,116 @@
+using System;
+using System.Buffers;
+
+namespace ytLive.Services.Compositor;
+
+/// <summary>
+/// The zoom box's magnifier (creator-corrected model, 2026-10-08): the box is a
+/// detached 2x view of a FIXED capture window — the box/2 region centred on the
+/// spot the creator clicked — sampled from the ALREADY-COMPOSITED frame (every
+/// layer: live backdrop, art, webcam, sources, alerts). Moving the box relocates
+/// it on screen without changing the capture; the box is painted LAST (layer n+1)
+/// so it sits above everything. The capture snapshot is taken before the box is
+/// drawn, so a box overlapping its own source never recurses.
+/// </summary>
+internal static class ZoomMagnifier
+{
+    /// <summary>
+    /// Magnify a box/2 capture window onto a box/2&#x2009;² box in <paramref name="dst"/>
+    /// (an opaque, already-composited crop-space buffer). dst pixel centres map to
+    /// capture coords as <c>cap + (dstLocal + 0.5) / 2</c> — the exact 2x the preview's
+    /// VisualBrush shows via a box/2 Viewbox with Stretch=Fill. <paramref name="round"/>
+    /// clips the box to a true circle (zoom shape Circle).
+    /// </summary>
+    internal static void MagnifyInto(
+        byte[] dst, int dstW, int dstH,
+        double boxX, double boxY, double boxW, double boxH,
+        double capX, double capY,
+        bool round)
+    {
+        if (boxW <= 0 || boxH <= 0) return;
+        if (dstW <= 0 || dstH <= 0) return;
+
+        // Integer box draw bounds (clamped to the buffer).
+        var bx0 = Math.Max(0, (int)Math.Floor(boxX));
+        var by0 = Math.Max(0, (int)Math.Floor(boxY));
+        var bx1 = Math.Min(dstW, (int)Math.Ceiling(boxX + boxW));
+        var by1 = Math.Min(dstH, (int)Math.Ceiling(boxY + boxH));
+        if (bx0 >= bx1 || by0 >= by1) return;
+        var bw = bx1 - bx0;
+        var bh = by1 - by0;
+
+        // Integer capture-window read bounds (the 2x window is box/2, clamped).
+        var rx0 = Math.Max(0, (int)Math.Floor(capX));
+        var ry0 = Math.Max(0, (int)Math.Floor(capY));
+        var rx1 = Math.Min(dstW, (int)Math.Ceiling(capX + boxW / 2.0));
+        var ry1 = Math.Min(dstH, (int)Math.Ceiling(capY + boxH / 2.0));
+        var rw = rx1 - rx0;
+        var rh = ry1 - ry0;
+        if (rw <= 0 || rh <= 0) return;
+
+        // Snapshot the capture first: the box may overlap its own source region.
+        var src = ArrayPool<byte>.Shared.Rent(rw * rh * 4);
+        try
+        {
+            for (var y = 0; y < rh; y++)
+                Buffer.BlockCopy(dst, ((ry0 + y) * dstW + rx0) * 4, src, y * rw * 4, rw * 4);
+
+            var radius = Math.Min(boxW, boxH) / 2.0;
+            var ccx = boxX + boxW / 2.0;
+            var ccy = boxY + boxH / 2.0;
+
+            for (var y = 0; y < bh; y++)
+            {
+                var dy = by0 + y;
+                var sy = capY + (dy + 0.5 - boxY) * 0.5 - ry0;
+                if (sy < 0.0) sy = 0.0;
+                if (sy > rh - 1.0) sy = rh - 1.0;
+                var syi = (int)sy;
+                var syInv = Math.Min(syi + 1, rh - 1);
+                var fy8 = (int)((sy - syi) * 256);
+                var fyInv = 256 - fy8;
+
+                var di = (dy * dstW + bx0) * 4;
+                for (var x = 0; x < bw; x++, di += 4)
+                {
+                    var dx = bx0 + x;
+                    if (round)
+                    {
+                        var ox = dx - ccx;
+                        var oy = dy - ccy;
+                        if (ox * ox + oy * oy > radius * radius) continue;
+                    }
+                    var sx = capX + (dx + 0.5 - boxX) * 0.5 - rx0;
+                    if (sx < 0.0) sx = 0.0;
+                    if (sx > rw - 1.0) sx = rw - 1.0;
+                    var sxi = (int)sx;
+                    var sxInv = Math.Min(sxi + 1, rw - 1);
+                    var fx8 = (int)((sx - sxi) * 256);
+                    var fxInv = 256 - fx8;
+
+                    var p00 = (syi * rw + sxi) * 4;
+                    var p10 = (syi * rw + sxInv) * 4;
+                    var p01 = (syInv * rw + sxi) * 4;
+                    var p11 = (syInv * rw + sxInv) * 4;
+                    dst[di] = (byte)Bilinear(src[p00], src[p10], src[p01], src[p11], fx8, fxInv, fy8, fyInv);
+                    dst[di + 1] = (byte)Bilinear(src[p00 + 1], src[p10 + 1], src[p01 + 1], src[p11 + 1], fx8, fxInv, fy8, fyInv);
+                    dst[di + 2] = (byte)Bilinear(src[p00 + 2], src[p10 + 2], src[p01 + 2], src[p11 + 2], fx8, fxInv, fy8, fyInv);
+                    dst[di + 3] = 255;
+                }
+            }
+        }
+        finally
+        {
+            ArrayPool<byte>.Shared.Return(src);
+        }
+    }
+
+    /// <summary>Two-stage bilinear in 8.8 fixed point (same precision as
+    /// <see cref="SceneCompositor"/>'s sampler).</summary>
+    private static int Bilinear(int tl, int tr, int bl, int br, int fx8, int fxInv, int fy8, int fyInv)
+    {
+        var top = tl * fxInv + tr * fx8;
+        var bot = bl * fxInv + br * fx8;
+        return (top * fyInv + bot * fy8 + 32768) >> 16;
+    }
+}

Services/Encoder/FfmpegArgs.cs

@@ -2,7 +2,9 @@ namespace ytLive.Services.Encoder;
 
 /// <summary>
 /// Builds the FFmpeg command line for a live RTMP push (TASK 4 ship step 3):
-/// raw BGRA frames via stdin (paced <c>-re</c>), real audio via the named pipe
+/// raw BGRA frames via stdin (paced by the frame pump — the pump holds a strict
+/// CFR cadence, so <c>-re</c> would only add a second, fighting pacer), real
+/// audio via the named pipe
 /// (TASK 9 — the mixer streams f32le at 48 kHz stereo into <c>\\.\pipe\&lt;name&gt;</c>;
 /// WASAPI loopback + the mic ride the pipe instead of the old anullsrc silence),
 /// H.264 + AAC encoding, FLV muxing to the ingestion URL. Pure — the encoder
@@ -16,7 +18,6 @@ public static class FfmpegArgs
         {
             "-hide_banner", "-loglevel", "info",
             "-stats", "-stats_period", "0.5",
-            "-re",
             "-f", "rawvideo", "-pix_fmt", "bgra",
             "-video_size", $"{options.Width}x{options.Height}",
             "-framerate", options.Fps.ToString(),

Services/Encoder/FfmpegEncoder.cs

@@ -1,4 +1,6 @@
+using System.Buffers;
 using System.Diagnostics;
+using System.Threading.Channels;
 using ytLive.Helpers;
 using ytLive.Models;
 
@@ -30,6 +32,21 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
     private Task? _stderrLoop;
     private bool _stopRequested;
 
+    // Pipe decoupling (slice 10, 2026-09-10): a bounded pending-frame queue drained
+    // by its own task (the OBS video-thread → encoder-queue model — the encoder's
+    // thread never couples back into the video thread; libobs obs-encoder.c). The
+    // pump's SubmitFrameAsync now ENQUEUES (copying into a pooled buffer) instead of
+    // blocking on WriteAsync when ffmpeg lags the pipe; overflow DROPS the newest
+    // frame (skip-newest) and counts it. BoundedChannelFullMode.Wait + TryWrite gives
+    // exactly that: when full, TryWrite returns false and the caller drops the item.
+    private const int QueueCapacity = 120; // ~2s at the tier's 60fps
+    private readonly Channel<PendingWrite> _frames = Channel.CreateBounded<PendingWrite>(
+        new BoundedChannelOptions(QueueCapacity) { SingleReader = true });
+    private Task? _drainTask;
+    private int _droppedBackpressure;
+
+    private readonly record struct PendingWrite(byte[] Buffer, int Length);
+
     public FfmpegEncoder(
         IFfmpegLocator locator,
         Func<IEncoderProcess>? processFactory = null)
@@ -40,6 +57,13 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
 
     public bool IsRunning { get; private set; }
 
+    /// <summary>Frames dropped by the bounded queue because the drain task couldn't
+    /// keep the pipe fed (the encoder lagging the real-time capture rate). The pump
+    /// reports this in its stats; the burned-in frame counter in the recording
+    /// shows the identical jumps. Distinct from <see cref="StreamHealth.DroppedFrames"/>
+    /// (ffmpeg's own progress-derived estimate).</summary>
+    public int DroppedFrames => Volatile.Read(ref _droppedBackpressure);
+
     public async Task StartAsync(EncoderOptions options, CancellationToken cancellationToken = default)
     {
         if (options == null) throw new ArgumentNullException(nameof(options));
@@ -93,26 +117,40 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
 
         _stopRequested = false;
         _stderrLoop = RunStderrLoopAsync(process);
+        StartDrainLoop(process);
     }
 
     /// <summary>
-    /// Write one raw BGRA frame to ffmpeg's stdin. Serialized internally; callers
-    /// (the compositor pump) may race freely. Frames are written as-is — the caller
-    /// paces to capture rate (the compositor's job, ship step 5).
+    /// Enqueue one raw BGRA frame for ffmpeg's stdin (slice 10). The caller races
+    /// freely (the compositor pump); this never blocks on the pipe. The pixels are
+    /// copied into a pooled buffer first because — unlike the old direct write — the
+    /// write happens later on the drain thread, so the caller may (and does) recycle
+    /// its scratch buffer the moment this returns. When the bounded queue is full the
+    /// NEWEST frame is dropped and counted (freshness over coverage; the encoder is
+    /// already behind, so the stale-content failure mode never encodes).
     /// </summary>
-    public async Task SubmitFrameAsync(VideoFrame frame, CancellationToken cancellationToken = default)
+    public Task SubmitFrameAsync(VideoFrame frame, CancellationToken cancellationToken = default)
     {
         if (frame == null) throw new ArgumentNullException(nameof(frame));
-        IEncoderProcess? process;
         lock (_gate)
         {
             if (!IsRunning) throw new InvalidOperationException("The encoder is not running.");
-            process = _process;
         }
 
-        var bytes = frame.BgraPixels;
-        await process!.StandardInput.WriteAsync(bytes, cancellationToken).ConfigureAwait(false);
-        await process.StandardInput.FlushAsync(cancellationToken).ConfigureAwait(false);
+        if (cancellationToken.IsCancellationRequested)
+            return Task.FromCanceled(cancellationToken);
+
+        var pooled = ArrayPool<byte>.Shared.Rent(frame.BgraPixels.Length);
+        Buffer.BlockCopy(frame.BgraPixels, 0, pooled, 0, frame.BgraPixels.Length);
+        if (_frames.Writer.TryWrite(new PendingWrite(pooled, frame.BgraPixels.Length)))
+            return Task.CompletedTask;
+
+        // Queue full (encoder lagging) or the channel completed during stop — drop the
+        // newest and count it. The caller never blocks; the encoder catches up or the
+        // session ends with a (reported) short gap instead of a frozen stall.
+        ArrayPool<byte>.Shared.Return(pooled);
+        Interlocked.Increment(ref _droppedBackpressure);
+        return Task.CompletedTask;
     }
 
     public async Task StopAsync(CancellationToken cancellationToken = default)
@@ -127,13 +165,17 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
             loop = _stderrLoop;
         }
 
+        // Flush every queued frame, then EOF: TryComplete lets the drain task write
+        // the buffered frames, close stdin → ffmpeg finalizes and exits by itself
+        // (the "did not exit after EOF" kill below is only the backstop).
         try
         {
-            process!.StandardInput.Dispose(); // EOF → ffmpeg finalizes + exits
+            _frames.Writer.TryComplete();
+            if (_drainTask != null) await _drainTask.ConfigureAwait(false);
         }
         catch (Exception ex)
         {
-            AppLog.Write(ex, "FFmpeg encoder: closing stdin failed");
+            AppLog.Write(ex, "FFmpeg encoder: drain loop faulted during stop");
         }
 
         try
@@ -178,6 +220,7 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
 
     public void Dispose()
     {
+        _frames.Writer.TryComplete(); // unblock a stuck drain loop alongside the kill
         lock (_gate)
         {
             if (!IsRunning) return;
@@ -188,6 +231,54 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
         }
     }
 
+    /// <summary>
+    /// The drain task (slice 10): owns every stdin write, so pipe backpressure — the
+    /// pump's old stall — lives HERE, on a thread the pump never touches. Frames are
+    /// written exactly as queued (the pooled array through its recorded length —
+    /// ArrayPool may return a larger buffer), returned to the pool after the write
+    /// copies into the pipe, and stdin is closed (EOF) once the queue drains.
+    /// </summary>
+    private void StartDrainLoop(IEncoderProcess process)
+    {
+        _drainTask = Task.Run(async () =>
+        {
+            try
+            {
+                try
+                {
+                    while (await _frames.Reader.WaitToReadAsync().ConfigureAwait(false))
+                    {
+                        while (_frames.Reader.TryRead(out var pending))
+                        {
+                            await process.StandardInput.WriteAsync(pending.Buffer, 0, pending.Length)
+                                .ConfigureAwait(false);
+                            await process.StandardInput.FlushAsync().ConfigureAwait(false);
+                            ArrayPool<byte>.Shared.Return(pending.Buffer);
+                        }
+                    }
+                }
+                catch (ChannelClosedException)
+                {
+                    // channel completed while waiting — fall through to EOF
+                }
+                catch (Exception ex)
+                {
+                    AppLog.Write(ex, "FFmpeg encoder: drain loop write faulted");
+                }
+                finally
+                {
+                    // EOF on every path — a byte that sits in the pool when the pipe
+                    // breaks is garbage anyway, and ffmpeg MUST see the close to finalize.
+                    process.StandardInput.Dispose();
+                }
+            }
+            catch (Exception ex)
+            {
+                AppLog.Write(ex, "FFmpeg encoder: drain loop faulted");
+            }
+        });
+    }
+
     private async Task<string> ProbeEncoderAsync(string ffmpegPath, CancellationToken cancellationToken)
     {
         try
@@ -230,14 +321,35 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
                     OnStderrLine(process, line);
                 }
 
-                var code = process.ExitCode;
-                var stillRunning = false;
-                lock (_gate) stillRunning = IsRunning;
-                if (stillRunning && !_stopRequested && code != 0)
+                // Read the exit code defensively: the stop path disposes the process
+                // while this loop may still be waking (2026-09-01 "No process is
+                // associated with this object" — a cosmetic race that poisoned the log).
+                int exitCode;
+                try
                 {
-                    AppLog.Write($"FFmpeg encoder: subprocess exited unexpectedly ({code})");
-                    _health.LastError = $"FFmpeg exited with code {code}";
-                    ProcessFailed?.Invoke(this, $"FFmpeg exited with code {code}");
+                    exitCode = process.ExitCode;
+                }
+                catch (Exception)
+                {
+                    exitCode = -1;
+                }
+
+                var stillRunning = false;
+                var stopping = false;
+                lock (_gate)
+                {
+                    stillRunning = IsRunning;
+                    stopping = _stopRequested;
+                }
+                if (stillRunning && !stopping)
+                {
+                    // ANY exit we did not ask for is a failure — including code 0.
+                    // The old `code != 0` gate let ffmpeg's clean early exit vanish
+                    // without a word while the pump kept feeding a corpse
+                    // (2026-09-01 first real recording: died at ~0.9s, zero logs).
+                    AppLog.Write($"FFmpeg encoder: subprocess exited unexpectedly (code {exitCode})");
+                    _health.LastError = $"FFmpeg exited with code {exitCode}";
+                    ProcessFailed?.Invoke(this, $"FFmpeg exited with code {exitCode}");
                 }
             }
             catch (Exception ex)
@@ -250,7 +362,17 @@ public sealed class FfmpegEncoder : IFfmpegEncoder
     private void OnStderrLine(IEncoderProcess process, string line)
     {
         var progress = FfmpegProgressParser.TryParse(line);
-        if (progress == null) return;
+        if (progress == null)
+        {
+            // THE EYES: everything ffmpeg says that isn't a progress line — startup
+            // config, warnings, the real reason it quit. Was silently discarded
+            // (2026-09-01: encoder died at ~0.9s, log silent). Truncated so a
+            // \r-choked stats blob can't flood; noise now beats blindness.
+            var text = line.Trim('\r', ' ', '\t');
+            if (text.Length > 0)
+                AppLog.Write($"ffmpeg: {(text.Length > 400 ? text[..400] + "…" : text)}");
+            return;
+        }
 
         var dropped = Math.Max(0, (long)Math.Round(progress.Value.Fps * progress.Value.Duration.TotalSeconds) - progress.Value.Frame);
 

Services/Encoder/FfmpegLocator.cs

@@ -1,125 +1,81 @@
 using System.IO;
-using System.IO.Compression;
-using System.Net.Http;
 using ytLive.Helpers;
 
 namespace ytLive.Services.Encoder;
 
 /// <summary>
-/// The default <see cref="IFfmpegLocator"/>: probe PATH first (the user's own
-/// install wins), then the cache in <c>%APPDATA%\ytLlive\tools</c>, then pull the
-/// pinned BtbN **lgpl-shared** build (TASK 4 ship step 2). The shared variant is a
-/// deliberate licensing choice: dynamic linking means LGPL compliance is "license
-/// text + source offer", with no static-relink (LGPL §6) material required. The
-/// shared zip puts <c>ffmpeg.exe</c> plus the <c>libav*.dll</c> family in <c>bin/</c>,
-/// so both are extracted — Windows resolves the DLLs from the exe's own directory.
-/// Search dirs, tools dir, and the downloader are constructor-injected so tests
-/// fake the network and stay on a temp directory.
+/// The default <see cref="IFfmpegLocator"/>: resolve the <b>bundled</b> FFmpeg that ships
+/// next to the app, falling back to PATH for anyone who deliberately installed their own.
+///
+/// <para><b>Nothing is downloaded.</b> This type used to pin a BtbN release URL, download
+/// the zip on first run, and execute it — which is Windows Store policy 10.2.2 (dynamic
+/// code inclusion, cited in <c>TASKS/research-store-certification.md</c> §4) and already
+/// cost a real failure: the pin aged out of BtbN's 14-day retention and the download
+/// <b>404'd on the creator's first real recording attempt</b> (2026-09-01). The binaries
+/// are now fetched at BUILD time by <c>scripts/fetch-ffmpeg.sh</c> (pinned URL + SHA-256)
+/// and copied into <c>ffmpeg/</c> beside the executable.</para>
+///
+/// <para><b>Order is bundled-first, deliberately.</b> The old code probed PATH first
+/// ("the user's own install wins"). With a bundle in the package that is the wrong way
+/// round: a random PATH <c>ffmpeg</c> may be a different major version or a GPL build, and
+/// the bundle is the one we pinned, license-vetted, and tested against. PATH stays as the
+/// escape hatch, which is what it is actually good for.</para>
+///
+/// <para>The lgpl-<b>shared</b> variant is a licensing choice, not a packaging one: dynamic
+/// linking makes LGPL compliance "license text + source offer" with no static-relink
+/// (LGPL §6) material required. That means the <c>libav*.dll</c> family must sit in the
+/// same folder as the exe — Windows resolves them from the executable's own directory.</para>
 /// </summary>
 public sealed class FfmpegLocator : IFfmpegLocator
 {
     public const string FileName = "ffmpeg.exe";
 
-    /// <summary>Pinned BtbN LGPL-shared win64 build (immutable autobuild tag; see TASKS.md).</summary>
-    public const string PinnedUrl =
-        "https://github.com/BtbN/FFmpeg-Builds/releases/download/autobuild-2026-08-09-13-03/ffmpeg-master-latest-win64-lgpl-shared.zip";
+    /// <summary>Sibling probe binary — bundled alongside ffmpeg so the media
+    /// frame-rate probe (<see cref="ytLive.Services.FfmpegFrameRateProbe"/>) can
+    /// derive its path from the located ffmpeg directory.</summary>
+    public const string ProbeFileName = "ffprobe.exe";
+
+    /// <summary>Folder, relative to the app base directory, that the build copies the
+    /// bundled build into. One folder for the exe and every DLL.</summary>
+    public const string BundleFolderName = "ffmpeg";
+
+    /// <summary>Base directory the bundle is resolved against. Injectable so tests can
+    /// point at a temp tree; defaults to the running app's base directory.</summary>
+    private readonly string _bundleRoot;
 
     private readonly string[] _searchDirs;
-    private readonly string _toolsDir;
-    private readonly Func<string, CancellationToken, Task<byte[]>> _downloader;
 
-    public FfmpegLocator(
-        string[]? searchDirs = null,
-        string? toolsDir = null,
-        Func<string, CancellationToken, Task<byte[]>>? downloader = null)
+    public FfmpegLocator(string[]? searchDirs = null, string? bundleRoot = null)
     {
         _searchDirs = searchDirs ?? ParsePath();
-        _toolsDir = toolsDir ?? Path.Combine(
-            Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "ytLlive", "tools");
-        _downloader = downloader ?? DefaultDownload;
+        _bundleRoot = bundleRoot ?? AppContext.BaseDirectory;
     }
 
-    public async Task<string> LocateAsync(CancellationToken cancellationToken = default)
+    public Task<string> LocateAsync(CancellationToken cancellationToken = default)
     {
+        var bundled = Path.Combine(_bundleRoot, BundleFolderName, FileName);
+        if (IsUsable(bundled)) return Task.FromResult(bundled);
+
         foreach (var dir in _searchDirs)
         {
             if (string.IsNullOrEmpty(dir)) continue;
             var candidate = Path.Combine(dir, FileName);
-            if (File.Exists(candidate)) return candidate;
+            if (IsUsable(candidate)) return Task.FromResult(candidate);
         }
 
-        var cached = Path.Combine(_toolsDir, FileName);
-        if (File.Exists(cached) && new FileInfo(cached).Length > 0) return cached;
-
-        try
-        {
-            var zip = await _downloader(PinnedUrl, cancellationToken).ConfigureAwait(false);
-            if (zip.Length == 0)
-                throw new IOException($"FFmpeg download from {PinnedUrl} returned an empty payload.");
-            Directory.CreateDirectory(_toolsDir);
-            ExtractBinaries(zip, _toolsDir);
-            return cached;
-        }
-        catch (Exception ex) when (ex is IOException or InvalidDataException or NotSupportedException)
-        {
-            AppLog.Write(ex, "FFmpeg locator: download/extract failed");
-            throw;
-        }
+        // Deliberately loud. The previous cache-then-download ladder had a "found
+        // something on disk" path that could satisfy a missing bundle with a stale copy,
+        // which is exactly the silent-drift a certification-gated dependency must not
+        // have. If the package forgot ffmpeg/, the app says so and stops.
+        throw new IOException(
+            $"FFmpeg was not found. The bundled copy is missing from " +
+            $"'{Path.Combine(_bundleRoot, BundleFolderName)}' — this build is incomplete " +
+            "(reinstall or re-fetch with scripts/fetch-ffmpeg.sh). Installing an LGPL-shared " +
+            "FFmpeg and putting 'ffmpeg' on PATH also works.");
     }
 
-    /// <summary>
-    /// Extract <c>ffmpeg.exe</c> and every <c>*.dll</c> into <c>toolsDir</c> via a
-    /// staging directory, so a failed extract never leaves a partially-populated
-    /// cache behind (the previous good cache stays until every move succeeds).
-    /// </summary>
-    private static void ExtractBinaries(byte[] zip, string toolsDir)
-    {
-        var staging = toolsDir + ".stage";
-        if (Directory.Exists(staging)) Directory.Delete(staging, recursive: true);
-        Directory.CreateDirectory(staging);
-        try
-        {
-            using var stream = new MemoryStream(zip, writable: false);
-            using var archive = new ZipArchive(stream, ZipArchiveMode.Read);
-            var exe = archive.Entries.FirstOrDefault(
-                    e => e.FullName.EndsWith("/" + FileName, StringComparison.OrdinalIgnoreCase))
-                ?? throw new InvalidDataException($"The pinned FFmpeg archive does not contain {FileName}.");
-            ExtractOne(exe, Path.Combine(staging, FileName));
-            foreach (var entry in archive.Entries)
-            {
-                if (entry.FullName.EndsWith(".dll", StringComparison.OrdinalIgnoreCase))
-                    ExtractOne(entry, Path.Combine(staging, Path.GetFileName(entry.FullName)));
-            }
-            foreach (var file in Directory.GetFiles(staging))
-                File.Move(file, Path.Combine(toolsDir, Path.GetFileName(file)), overwrite: true);
-        }
-        finally
-        {
-            if (Directory.Exists(staging)) Directory.Delete(staging, recursive: true);
-        }
-    }
-
-    private static void ExtractOne(ZipArchiveEntry entry, string destination)
-    {
-        var temp = destination + ".tmp";
-        try
-        {
-            using (var source = entry.Open())
-            using (var target = File.Create(temp))
-                source.CopyTo(target);
-            File.Move(temp, destination);
-        }
-        finally
-        {
-            if (File.Exists(temp)) File.Delete(temp);
-        }
-    }
-
-    private static async Task<byte[]> DefaultDownload(string url, CancellationToken ct)
-    {
-        using var http = new HttpClient { Timeout = TimeSpan.FromMinutes(10) };
-        return await http.GetByteArrayAsync(url, ct).ConfigureAwait(false);
-    }
+    private static bool IsUsable(string path) =>
+        File.Exists(path) && new FileInfo(path).Length > 0;
 
     private static string[] ParsePath()
     {

Services/Encoder/FramePump.cs

@@ -29,15 +29,98 @@ public sealed class FramePump : IDisposable
     private readonly Action<string>? _log;
     private readonly Func<TimeSpan, CancellationToken, Task> _pacingDelay;
     private readonly Func<(VideoFrame? Frame, SocialBarPosition Position)>? _socialBar;
+    private readonly Func<VideoFrame?>? _alertTicker;
+    private readonly Func<VideoFrame?>? _brandFlash;
     private readonly TransitionService? _transition;
-    private readonly Func<Scene?>? _fromSceneProvider;
+    private readonly SceneGraph? _sceneGraph;
     private readonly SceneCompositor _compositor = new();
 
+    /// <summary>Per-stage composite timing for the CURRENT stats window (webcam-cadence
+    /// unit, 2026-10-16): the compositor records each stage into this collector and
+    /// <see cref="ReportStats"/> logs the averaged breakdown, then clears it — the
+    /// "which of the 6 elements eats ~140ms" reading (see the parts line).</summary>
+    private readonly CompositeTimings _timings = new();
+
+    // Master-buffer scratch pool (take-4 starvation fix, slice 2 of 2): a fresh
+    // 8.3MB byte[] every tick is ~500MB/s of LOH churn — GC stalls masquerading
+    // as render cost. The pump pools ONLY buffers it handed out (reference-equality
+    // set), so bake-cache / social-bar / static-cache frames are never touched;
+    // SubmitFrameAsync copies the bytes to the encoder's stdin before returning,
+    // so recycling after submit is safe (MyMistakes recipe).
+    private readonly HashSet<byte[]> _ownedScratch = new(ReferenceEqualityComparer.Instance);
+    private readonly List<byte[]> _freeScratch = new();
+    private const int MaxScratchPooled = 4;
+
+    private byte[] AcquireScratch(int size)
+    {
+        for (var i = _freeScratch.Count - 1; i >= 0; i--)
+        {
+            if (_freeScratch[i].Length != size) continue;
+            var buffer = _freeScratch[i];
+            _freeScratch.RemoveAt(i);
+            return buffer;
+        }
+        var fresh = new byte[size];
+        _ownedScratch.Add(fresh);
+        return fresh;
+    }
+
+    private void ReleaseScratch(byte[]? buffer)
+    {
+        if (buffer == null || !_ownedScratch.Contains(buffer)) return;
+        if (_freeScratch.Count >= MaxScratchPooled || _freeScratch.Contains(buffer)) return;
+        _freeScratch.Add(buffer);
+    }
+
+    // Windows sleep quantum (take-9 finding, 2026-09-04): Task.Delay rounds every
+    // request up to the system clock tick (~15.6ms default — learn.microsoft.com/en-us/
+    // dotnet/api/system.threading.tasks.task.delay: "approximately 15 milliseconds on
+    // Windows systems"), so a pacer requesting 3-15ms actually sleeps 15.6ms. Takes
+    // 5-9 measured work ~25ms but period ~37ms: one padded wait per frame hid every
+    // compositor improvement. Established media-app practice (game-loop/OBS canon —
+    // stackoverflow.com/questions/5441464; and raise the resolution for the session —
+    // learn.microsoft.com/en-us/windows/win32/api/timeapi/nf-timeapi-timebeginperiod):
+    // timeBeginPeriod(1) while the pump runs, sleep only the BULK of the remainder,
+    // and spin the last ~2ms across the deadline.
+    [System.Runtime.InteropServices.DllImport("winmm.dll")]
+    private static extern uint timeBeginPeriod(uint uMilliseconds);
+    [System.Runtime.InteropServices.DllImport("winmm.dll")]
+    private static extern uint timeEndPeriod(uint uMilliseconds);
+    private static readonly long SpinTailTicks = System.Diagnostics.Stopwatch.Frequency * 2 / 1000; // 2ms
+
     private readonly object _gate = new();
     private IFfmpegEncoder? _encoder;
     private CancellationTokenSource? _cts;
     private Task? _pumpTask;
     private bool _started;
+    private long _outputIndex;
+
+    /// <summary>Captured by <see cref="ProbeRender"/> when a render exceeds ~20ms —
+    /// the 2026-09-12 half-speed-render probe. Appended (once) to the next stats or
+    /// stall line, then cleared.</summary>
+    private string _renderDetail = "";
+
+    /// <summary>C4 blit-on-change cache (2026-09-15): the FULL-render path (split=0
+    /// when the live-capture backdrop sits at element 0, or no SceneGraph) re-composites
+    /// the ENTIRE frame every tick even when no input changed — the ty-1841 take logged
+    /// a render stall on EVERY iteration (totalMs 21-44, one composite per ~30ms while
+    /// the content moved ~20 updates/s). The SceneGraph split can never help here: the
+    /// backdrop is element 0 and must stay dynamic (a baked capture goes stale), so the
+    /// cache lives at the pump: the last full-render output plus the input identity that
+    /// produced it. Unchanged identity → ONE BlockCopy (~3ms) reuses the composite;
+    /// changed identity → re-composite. The cache buffer is a SEPARATE long-lived array,
+    /// never the scratch pool — the caller burns the frame counter and recycles the
+    /// scratch AFTER RenderScene returns, so the cache is written from the rendered
+    /// scratch BEFORE returning (pre-burn, pre-recycle). The identity mirror is
+    /// <see cref="BuildFullRenderSignature"/>: it resolves the same frames the compositor
+    /// will (same resolver seam), so a changed frame (new capture, new webcam, new chat
+    /// raster) forces a re-render and an unchanged one never serves stale bytes. Internal
+    /// counters feed the Good Dog test + the 5s cache detail in the stats line.</summary>
+    private byte[]? _fullCachePixels;
+    private bool _fullCacheValid;
+    private ulong _lastFullSignature;
+    internal long CacheHits;
+    internal long CacheRenders;
 
     /// <summary>Forwards the encoder's parsed health — ship step 6 binds this to the bottom bar.</summary>
     public event EventHandler<StreamHealth>? HealthUpdated;
@@ -54,8 +137,10 @@ public sealed class FramePump : IDisposable
         Action<string>? log = null,
         Func<TimeSpan, CancellationToken, Task>? pacingDelay = null,
         Func<(VideoFrame? Frame, SocialBarPosition Position)>? socialBar = null,
+        Func<VideoFrame?>? alertTicker = null,
+        Func<VideoFrame?>? brandFlash = null,
         TransitionService? transition = null,
-        Func<Scene?>? fromSceneProvider = null)
+        SceneGraph? sceneGraph = null)
     {
         _sceneProvider = sceneProvider ?? throw new ArgumentNullException(nameof(sceneProvider));
         _frameResolver = frameResolver ?? throw new ArgumentNullException(nameof(frameResolver));
@@ -65,12 +150,19 @@ public sealed class FramePump : IDisposable
         _log = log;
         _pacingDelay = pacingDelay ?? ((delay, ct) => Task.Delay(delay, ct));
         _socialBar = socialBar;
+        _alertTicker = alertTicker;
+        _brandFlash = brandFlash;
         _transition = transition;
-        _fromSceneProvider = fromSceneProvider;
+        _sceneGraph = sceneGraph;
     }
 
     public bool IsRunning { get; private set; }
 
+    /// <summary>The burned counter of the LAST frame submitted to the encoder. Stable
+    /// across a tick's multiple resolver passes (it advances only at burn/submit, which
+    /// happens AFTER render) — tests key per-tick content on it.</summary>
+    internal long OutputIndex => _outputIndex;
+
     /// <summary>Never throws: failures are logged and surfaced via <see cref="Failed"/>,
     /// so the VM can fire-and-forget it from a sync command handler.</summary>
     public async Task StartAsync(CancellationToken cancellationToken = default)
@@ -107,8 +199,20 @@ public sealed class FramePump : IDisposable
             // synchronously on this thread before PumpAsync even returns.
             IsRunning = true;
             _cts = new CancellationTokenSource();
-            _pumpTask = PumpAsync(options, _cts.Token);
-            _log?.Invoke($"FramePump started ({options.Width}×{options.Height} @ {options.Fps} fps)");
+            // The loop runs on the thread pool ON PURPOSE (take-8 finding, 2026-09-04):
+            // Task.Run installs no SynchronizationContext, so every await continuation
+            // stays off the UI dispatcher. Before this, the pump inherited the UI
+            // thread's sync context (StartAsync is fired from a command handler), so
+            // "render 22ms, wait 10ms" was the producer sitting in the dispatcher
+            // queue behind the live preview it is meant to be independent of — the
+            // stats quantum fix made the wait VISIBLE; this removes its cause.
+            // OBS's video threads are dedicated for exactly this reason.
+            _pumpTask = Task.Run(() => PumpAsync(options, _cts.Token));
+            var scene = _sceneProvider();
+            var comp = _compositorOptions();
+            _log?.Invoke($"FramePump started ({options.Width}×{options.Height} @ {options.Fps} fps)" +
+                         (scene != null ? $" scene='{scene.Name}'" : "") +
+                         $" comp={comp.SourceRectWidth}x{comp.SourceRectHeight}");
         }
         catch (Exception ex)
         {
@@ -208,6 +312,8 @@ public sealed class FramePump : IDisposable
         {
             _log?.Invoke($"FramePump: dispose failed: {ex.Message}");
         }
+        _freeScratch.Clear();
+        _ownedScratch.Clear();
     }
 
     private async Task PumpAsync(EncoderOptions options, CancellationToken ct)
@@ -215,6 +321,136 @@ public sealed class FramePump : IDisposable
         var interval = TimeSpan.FromSeconds(1d / Math.Max(1, options.Fps));
         var lastTick = System.Diagnostics.Stopwatch.StartNew();
 
+        // Deadline pacing (2026-09-03, take-3 fix): the frame interval is a DEADLINE,
+        // not an afterthought sleep — the OBS libobs video-io.c pattern (researched
+        // before coding; see https://github.com/obsproject/obs-studio/blob/master/
+        // libobs/media-io/video-io.c). The old loop slept the FULL interval after
+        // each render, so period = render + submit + interval: at take-3's 258ms
+        // render that was 3.6fps stamped into a 60fps container — rawvideo stamps by
+        // arrival, so 30 wall-seconds muxed as a 2.1s time-lapse, no error anywhere.
+        var intervalTicks = Math.Max(1, (long)Math.Round(interval.TotalSeconds * System.Diagnostics.Stopwatch.Frequency));
+        var nextTick = System.Diagnostics.Stopwatch.GetTimestamp();
+
+        // Stage timing (2026-09-01, take two): rawvideo carries no per-frame
+        // timestamps — ffmpeg stamps frames by ARRIVAL at the declared fps. A producer
+        // slower than the declared rate yields a time-lapsed, short file (observed:
+        // 39 frames in 27 wall-seconds ≈ 30x at 60fps) with no error anywhere.
+        // Log the render/submit split every 5s so the next take names the stage.
+        var renderSw = new System.Diagnostics.Stopwatch();
+        var submitSw = new System.Diagnostics.Stopwatch();
+        var waitSw = new System.Diagnostics.Stopwatch();
+        // Resolve-vs-composite split (2026-09-04, take-6 ambiguity): "render" was a
+        // black box — the stats line now reports resolver time separately so a take
+        // names the stage (get-frame vs blit) instead of feeding another guess.
+        var resolveSw = new System.Diagnostics.Stopwatch();
+        long renderTicks = 0, submitTicks = 0, resolveTicks = 0, waitTicks = 0;
+        long socialBarTicks = 0, tickerTicks = 0, flashTicks = 0, acquireTicks = 0;
+        long worstRender = 0, worstSubmit = 0;
+        int statFrames = 0;
+        int stalls = 0;
+        long lastCacheHits = 0, lastCacheRenders = 0;
+        var statsNext = DateTime.UtcNow + TimeSpan.FromSeconds(5);
+        // bool _loggedStartDetail = false;
+
+        // Real-render accounting (UNIT 0, 2026-10-05): every average above was
+        // divided by statFrames — the number of frames SUBMITTED, which deadline
+        // padding always fills to the full target even when the renderer only
+        // produced a fifth of them. A 60fps container therefore reported "300/300
+        // frames, avg render 12ms" while the source actually fed it 60 distinct
+        // images. Render cost is now divided by the render count, and the render
+        // count is reported beside the submit count — the two numbers side by side
+        // ARE the duplicate-on-lag ratio, which is the only honest reading of how
+        // much of the stream is a repeat.
+        int statRenders = 0;
+
+        // Webcam cadence (UNIT 0, 2026-10-05): the pump sees each element's resolved
+        // frame, and VideoFrame.Epoch is the webcam ring's monotonic generation — so a
+        // NEW epoch means the webcam actually delivered something new between two of
+        // our ticks. This is the counterpart to MediaCaptureFrameSource's arrivals
+        // line: it measures what reached the OUTPUT, not what the camera produced. If
+        // the camera reports 30/s and this reports 25/s, the loss is between them.
+        var webcamCadence = new Helpers.FrameCadence();
+        var seenWebcamEpochs = new HashSet<long>();
+
+        void ReportStats()
+        {
+            if (DateTime.UtcNow < statsNext) return;
+            var target = 5d / interval.TotalSeconds; // frames expected per window
+            IFfmpegEncoder? encoder;
+            lock (_gate) encoder = _encoder;
+            var dropped = encoder == null ? 0 : encoder.DroppedFrames;
+            var detail = _renderDetail;
+            _renderDetail = "";
+            var cacheDetail = "";
+            if (statFrames > 0)
+            {
+                // C4 window detail: rendered composites (R) vs cache reuses (H) since the
+                // last report — hard numeric proof the blit-on-change cache engaged.
+                var hits = CacheHits - lastCacheHits;
+                var renders = CacheRenders - lastCacheRenders;
+                lastCacheHits = CacheHits;
+                lastCacheRenders = CacheRenders;
+                if (hits > 0 || renders > 0) cacheDetail = $", cache {renders}R/{hits}H";
+            }
+            double freq = System.Diagnostics.Stopwatch.Frequency;
+            _log?.Invoke(statFrames == 0
+                ? "FramePump stats: NO frames produced in 5s (loop stalled?)" + (detail.Length > 0 ? " | " + detail : "")
+                : $"FramePump stats: {statFrames}/{target:F0} frames per 5s from {statRenders} renders, " +
+                  $"avg render {renderTicks / freq * 1000 / Math.Max(1, statRenders):F1}ms " +
+                  $"(resolve {resolveTicks / freq * 1000 / Math.Max(1, statRenders):F1}, " +
+                  $"social {socialBarTicks / freq * 1000 / Math.Max(1, statRenders):F2}ms, " +
+                  $"ticker {tickerTicks / freq * 1000 / Math.Max(1, statRenders):F2}ms, " +
+                  $"flash {flashTicks / freq * 1000 / Math.Max(1, statRenders):F2}ms, " +
+                  $"acq {acquireTicks / freq * 1000 / Math.Max(1, statRenders):F2}ms), " +
+                  $"avg submit {submitTicks / freq * 1000 / statFrames:F1}ms, "
+                  + $"avg wait {waitTicks / freq * 1000 / Math.Max(1, statRenders):F1}ms, "
+                  + $"worst render {worstRender / freq * 1000:F1}ms, "
+                  + $"worst submit {worstSubmit / freq * 1000:F1}ms, "
+                  + $"dropped {dropped}, stalls {stalls}{cacheDetail}, {webcamCadence.Summarize().Describe("webcam")}"
+                  + (detail.Length > 0 ? " | " + detail : ""));
+
+            // Per-stage breakdown (webcam-cadence unit, 2026-10-16): the stats line above
+            // says WHAT a composite cost; this says WHERE it went — one entry per stage,
+            // slowest first, averaged per render so the numbers compare with `avg render`.
+            // No entries (fully-static shortcut, or every render a C4 cache hit) means no
+            // per-element work happened — that IS the reading. The sub-stage
+            // `#i <name> raster` is the paste-cache rasterize miss and nests in its
+            // element's total.
+            var parts = _timings.Describe(statRenders);
+            if (parts.Length > 0)
+                _log?.Invoke($"FramePump parts ({statRenders} renders/5s): {parts}");
+            _timings.Reset();
+
+            worstRender = 0;
+            worstSubmit = 0;
+            renderTicks = submitTicks = resolveTicks = waitTicks = 0;
+            socialBarTicks = tickerTicks = flashTicks = acquireTicks = 0;
+            statFrames = 0;
+            statRenders = 0;
+            stalls = 0;
+            webcamCadence.Reset();
+            seenWebcamEpochs.Clear();
+            statsNext = DateTime.UtcNow + TimeSpan.FromSeconds(5);
+        }
+
+        // One wrapper shared by every render of the run — resolve time accumulates
+        // inside the render measurement, and the stats line reports the split.
+        timeBeginPeriod(1); // pairs with timeEndPeriod in the finally — see field note
+        var previousGcMode = System.Runtime.GCSettings.LatencyMode;
+        System.Runtime.GCSettings.LatencyMode = System.Runtime.GCLatencyMode.SustainedLowLatency;
+        VideoFrame? TimedResolver(SceneElement element)
+        {
+            resolveSw.Restart();
+            var frame = _frameResolver(element);
+            resolveSw.Stop();
+            resolveTicks += resolveSw.ElapsedTicks;
+            if (element.IsWebcam && frame != null && seenWebcamEpochs.Add(frame.Epoch))
+                webcamCadence.Add(System.Diagnostics.Stopwatch.GetTimestamp());
+            return frame;
+        }
+
+        Scene? lastDumpedScene = null;
+
         try
         {
             while (!ct.IsCancellationRequested)
@@ -222,6 +458,19 @@ public sealed class FramePump : IDisposable
                 var scene = _sceneProvider();
                 if (scene != null)
                 {
+                    // Scene dump (webcam-cadence unit, 2026-10-16): the 141ms regression
+                    // could not be compared take-to-take because the log recorded no scene
+                    // shape at all. Dump it when the pump starts on a scene and whenever
+                    // the active scene changes — one header line plus one line per element
+                    // (z-index, name, kind, source type, visibility, rect, opacity, clip).
+                    if (!ReferenceEquals(scene, lastDumpedScene))
+                    {
+                        lastDumpedScene = scene;
+                        foreach (var line in FormatSceneDump(scene, _sceneGraph?.GetSplitPoint(scene) ?? -1))
+                            _log?.Invoke(line);
+                    }
+
+                    var iterStart = System.Diagnostics.Stopwatch.GetTimestamp();
                     var compositorOptions = _compositorOptions();
                     VideoFrame? socialBarFrame = null;
                     var socialBarTop = 0;
@@ -235,30 +484,125 @@ public sealed class FramePump : IDisposable
                                 : compositorOptions.SourceRectHeight - barFrame.Height;
                     }
 
+                    var sw = System.Diagnostics.Stopwatch.StartNew();
+                    VideoFrame? tickerFrame = _alertTicker?.Invoke();
+                    tickerTicks += sw.ElapsedTicks;
+                    sw.Restart();
+                    VideoFrame? flashFrame = _brandFlash?.Invoke();
+                    flashTicks += sw.ElapsedTicks;
+                    sw.Restart();
+                    var (barFrame2, position2) = (_socialBar == null ? (null, SocialBarPosition.Bottom) : _socialBar());
+                    socialBarFrame = barFrame2;
+                    socialBarTop = barFrame2 == null ? 0 : (position2 == SocialBarPosition.Top ? 0 : compositorOptions.SourceRectHeight - barFrame2.Height);
+                    socialBarTicks += sw.ElapsedTicks;
+
                     VideoFrame frame;
-                    if (_transition is { Active: true } transition && _fromSceneProvider != null)
+                    var scratchSize = compositorOptions.SourceRectWidth
+                        * compositorOptions.SourceRectHeight * 4;
+                    renderSw.Restart();
+                    sw.Restart();
+                    var scratch = AcquireScratch(scratchSize);
+                    acquireTicks += sw.ElapsedTicks;
+                    frame = RenderScene(scene, compositorOptions, socialBarFrame, socialBarTop, tickerFrame, flashFrame, scratch, TimedResolver, _timings);
+                    if (_transition is { Active: true } transition)
                     {
-                        var fromScene = _fromSceneProvider();
-                        var fromFrame = fromScene != null
-                            ? _compositor.Render(fromScene, _frameResolver, null, compositorOptions, socialBarFrame, socialBarTop)
-                            : _compositor.Render(scene, _frameResolver, null, compositorOptions, socialBarFrame, socialBarTop);
-                        var toFrame = _compositor.Render(scene, _frameResolver, null, compositorOptions, socialBarFrame, socialBarTop);
-                        frame = transition.BlendFrame(toFrame);
+                        frame = transition.BlendFrame(frame);
                         transition.Tick(lastTick.Elapsed.TotalMilliseconds);
-                        lastTick.Restart();
                     }
-                    else
-                    {
-                        frame = _compositor.Render(scene, _frameResolver, null, compositorOptions, socialBarFrame, socialBarTop);
+                    // Restarted EVERY frame (transition or not): a transition begun
+                    // after idle must not inherit a giant ElapsedMs and complete
+                    // instantly on its first Tick.
                     lastTick.Restart();
-                    }
+                    renderSw.Stop();
+                    renderTicks += renderSw.ElapsedTicks;
+                    if (renderSw.ElapsedTicks > worstRender) worstRender = renderSw.ElapsedTicks;
+                    statRenders++;
 
                     IFfmpegEncoder? encoder;
                     lock (_gate) encoder = _encoder;
                     if (encoder == null) break;
+
+                    // Deadline pacing, OBS duplicate-on-lag (slice 15): emit ONE frame per
+                    // deadline slot — a fresh composite when the render kept up, a REPEAT
+                    // of this iteration's latest composite for every slot the render
+                    // overran. The OBS model never leaves a wall-time hole: libobs
+                    // media-io/video-io.c runs on its own clock and duplicates the latest
+                    // frame when the video thread lags, logging "lagged frames due to
+                    // rendering lag/stalls" — never skipped time (docs.obsproject.com/
+                    // backend-design: "If the video frame queue is full, it will duplicate
+                    // the last frame"). Slice 10 chose the opposite for freshness: an
+                    // overrun SKIPPED the missed slots, so a 60fps-authoring pump emitting
+                    // one frame per 35ms overrun authored ~1.7x playback (ty-1726: 163
+                    // video frames for 2.93s of audio) and ended the video 0.22s before the
+                    // audio tail. Counting duplicates instead of skips keeps recording
+                    // duration == wall duration (no acceleration, no audio tail cut) at the
+                    // cost of a short judder during a stall — the accepted trade. The burst
+                    // is microseconds (the enqueue never blocks, and the loop is clamped to
+                    // deadlineNow) so it can't smear the way the take-9 blocking burst did.
+                    var deadlineNow = System.Diagnostics.Stopwatch.GetTimestamp();
+                    while (!ct.IsCancellationRequested && deadlineNow >= nextTick)
+                    {
+                        // Burned-in frame counter (slice 10 judge): a clock-independent
+                        // pacing witness burned literally into the composite. Decode the
+                        // recording and read the bottom-right strip: the number must
+                        // advance +1 per authored frame and jump only by counted drops
+                        // (queue overflow). Burned here — on the buffer finally submitted,
+                        // which the enqueue's snapshot copies before the next iteration
+                        // rewrites it — so every file frame carries its own index and a
+                        // fast-render iteration that submitted nothing leaves no phantom
+                        // gap (the slice-10 unconditional bump before the gate could).
+                        _outputIndex++;
+                        BurnFrameIndex(frame.BgraPixels, frame.Width, frame.Height, _outputIndex);
+
+                        submitSw.Restart();
                         await encoder.SubmitFrameAsync(frame, ct);
+                        submitSw.Stop();
+                        statFrames++;
+                        submitTicks += submitSw.ElapsedTicks;
+                        if (submitSw.ElapsedTicks > worstSubmit) worstSubmit = submitSw.ElapsedTicks;
+                        nextTick += intervalTicks;
+                    }
+
+                    // SubmitFrameAsync copied the bytes into the encoder's queue — the
+                    // tick's buffers are recyclable once the enqueue snapshot them.
+                    // The free-list Contains guard keeps the Cut path (BlendFrame
+                    // returns toFrame itself, aliasing scratch) safe.
+                    ReleaseScratch(frame.BgraPixels);
+                    ReleaseScratch(scratch);
+
+                    // Sleep the BULK of the remainder, SPIN the 2ms tail — never hand
+                    // a sub-tick remainder to the sleep quantum (the timeBeginPeriod
+                    // note). If the renderer already ate the budget there is nothing
+                    // left to sleep and the loop renders the next frame straight away.
+                    waitSw.Restart();
+                    var ahead = nextTick - System.Diagnostics.Stopwatch.GetTimestamp();
+                    if (ahead > SpinTailTicks)
+                        await _pacingDelay(TimeSpan.FromSeconds(
+                            (ahead - SpinTailTicks) / (double)System.Diagnostics.Stopwatch.Frequency), ct);
+                    while (!ct.IsCancellationRequested
+                           && System.Diagnostics.Stopwatch.GetTimestamp() < nextTick)
+                        Thread.SpinWait(400);
+                    waitSw.Stop();
+                    waitTicks += waitSw.ElapsedTicks;
+
+                    // Stall logger (slice 10): an iteration spanning more than two full
+                    // intervals is the old bug's fingerprint — name the stage instead of
+                    // guessing. With the queue, submit should be ~1ms, so a stall here
+                    // means RENDER or RESOLVE (the stage terms of the last take).
+                    var iterWall = System.Diagnostics.Stopwatch.GetTimestamp() - iterStart;
+                    if (iterWall > 2 * intervalTicks)
+                    {
+                        stalls++;
+                        var detail = _renderDetail;
+                        _renderDetail = "";
+                        _log?.Invoke($"FramePump stall: iteration {iterWall / (double)System.Diagnostics.Stopwatch.Frequency * 1000:F0}ms " +
+                            $"(> 2× the {interval.TotalMilliseconds:F0}ms interval): worst render " +
+                            $"{worstRender / (double)System.Diagnostics.Stopwatch.Frequency * 1000:F0}ms, worst submit " +
+                            $"{worstSubmit / (double)System.Diagnostics.Stopwatch.Frequency * 1000:F0}ms, dropped {encoder.DroppedFrames}" +
+                            (detail.Length > 0 ? " | " + detail : ""));
+                    }
+                    ReportStats();
                 }
-                await _pacingDelay(interval, ct);
             }
         }
         catch (OperationCanceledException)
@@ -281,12 +625,343 @@ public sealed class FramePump : IDisposable
         }
         finally
         {
+            System.Runtime.GCSettings.LatencyMode = previousGcMode;
+            timeEndPeriod(1);
             lock (_gate) IsRunning = false;
         }
     }
 
     private void OnHealthUpdated(object? sender, StreamHealth health) => HealthUpdated?.Invoke(this, health);
 
+    /// <summary>Render a scene, using the baked-crust optimization when a <see cref="SceneGraph"/>
+    /// is wired in: bake/cache the static layers below the split point, then composite the
+    /// dynamic/above-split layers per frame. Without a SceneGraph, falls back to a full render
+    /// (identical output — see SceneCompositorTests). <paramref name="scratch"/> is a pooled
+    /// master buffer when supplied; the fully-static path returns the bake-cache frame itself
+    /// (never pooled — the release side checks owned-by-reference).</summary>
+    private VideoFrame RenderScene(
+        Scene scene,
+        CompositorOptions options,
+        VideoFrame? socialBarFrame,
+        int socialBarTop,
+        VideoFrame? tickerFrame,
+        VideoFrame? flashFrame,
+        byte[]? scratch = null,
+        Func<SceneElement, VideoFrame?>? resolver = null,
+        CompositeTimings? timings = null)
+    {
+        resolver ??= _frameResolver;
+        if (_sceneGraph == null)
+        {
+            var sw = System.Diagnostics.Stopwatch.StartNew();
+            var frame = RenderFull(scene, options, socialBarFrame, socialBarTop, tickerFrame, flashFrame, scratch, resolver, timings);
+            ProbeRender("full-no-graph", scene, -1, sw.ElapsedMilliseconds, 0);
+            return frame;
+        }
+
+        var split = _sceneGraph.GetSplitPoint(scene);
+        if (split == scene.Elements.Count)
+        {
+            // Fully static scene: bake once, reuse.
+            var sw = System.Diagnostics.Stopwatch.StartNew();
+            var baked = _sceneGraph.GetBakedBase(scene, _frameResolver, _compositorOptions, timings: timings);
+            if (baked != null)
+            {
+                // BUG (pre-existing, found while wiring the branding credit 2026-09-26):
+                // this path returned the stretched bake and silently DROPPED the social
+                // bar and the alert ticker. Overlay() copies before blitting, so the
+                // cached bake is not mutated and the flash still cannot get sticky in it.
+                if (socialBarFrame != null || tickerFrame != null || flashFrame != null)
+                {
+                    var tOverlay = System.Diagnostics.Stopwatch.GetTimestamp();
+                    var withOverlays = baked;
+                    if (flashFrame != null) withOverlays = SceneCompositor.Overlay(withOverlays, options, flashFrame, 0, 0);
+                    if (tickerFrame != null) withOverlays = SceneCompositor.Overlay(withOverlays, options, tickerFrame, tickerFrame.OriginX, tickerFrame.OriginY);
+                    if (socialBarFrame != null) withOverlays = SceneCompositor.Overlay(withOverlays, options, socialBarFrame, socialBarTop, 0);
+                    baked = withOverlays;
+                    timings?.Add("overlay", System.Diagnostics.Stopwatch.GetTimestamp() - tOverlay);
+                }
+                var tScale = System.Diagnostics.Stopwatch.GetTimestamp();
+                var stretched = StretchMath.BilinearScale(baked, options.OutputWidth, options.OutputHeight);
+                timings?.Add("scale", System.Diagnostics.Stopwatch.GetTimestamp() - tScale);
+                ProbeRender("fully-static", scene, split, sw.ElapsedMilliseconds, (int)sw.ElapsedMilliseconds);
+                return stretched;
+            }
+        }
+
+        var swBase = System.Diagnostics.Stopwatch.StartNew();
+        var baseFrame = _sceneGraph.GetBakedBase(scene, _frameResolver, _compositorOptions, timings: timings);
+        if (baseFrame != null)
+        {
+            var frame = SceneCompositor.CompositeLayers(
+                baseFrame, scene, split, resolver, options, socialBarFrame, socialBarTop, flashFrame: flashFrame, tickerFrame: tickerFrame, scratch: scratch, timings: timings);
+            ProbeRender("base+layers", scene, split, swBase.ElapsedMilliseconds, 0);
+            return frame;
+        }
+
+        // No static base (first layer is dynamic or empty scene) — full render.
+        var swFull = System.Diagnostics.Stopwatch.StartNew();
+        var frame2 = RenderFull(scene, options, socialBarFrame, socialBarTop, tickerFrame, flashFrame, scratch, resolver, timings);
+        ProbeRender("full-render", scene, split, swFull.ElapsedMilliseconds, 0);
+        return frame2;
+    }
+
+    /// <summary>The full-render path (no SceneGraph, or no static base) wrapped in the
+    /// C4 blit-on-change cache: when every resolved input plus every element's
+    /// layout/visual bits match the last composite, reuse it with one BlockCopy instead
+    /// of re-compositing. Mirror the compositor's resolution <i>before</i> deciding so a
+    /// hit costs ~3ms of pure copy and a miss costs exactly the old full render.</summary>
+    private VideoFrame RenderFull(
+        Scene scene, CompositorOptions options, VideoFrame? socialBarFrame, int socialBarTop,
+        VideoFrame? tickerFrame, VideoFrame? flashFrame,
+        byte[]? scratch, Func<SceneElement, VideoFrame?> resolver,
+        CompositeTimings? timings = null)
+    {
+        // 1:1 guard: the cache stores the OUTPUT bytes and scratch is source-sized —
+        // at 1:1 they are the same buffer size. Off-size tiers (a vertical 1080×1920
+        // tier, an H264-1080p tier) fall back to a per-tick full render; the deployed
+        // config is master-sized and caching a per-tick fresh scale buffer is the known
+        // vertical-tier follow-up (see ai.md), not silently baked here.
+        var useCache = scratch != null && options.SourceRectWidth == options.OutputWidth
+            && options.SourceRectHeight == options.OutputHeight;
+        var signature = useCache
+            ? BuildFullRenderSignature(scene, options, socialBarFrame, socialBarTop, tickerFrame, flashFrame, resolver)
+            : 0UL;
+
+        if (useCache && _fullCacheValid && signature == _lastFullSignature
+            && _fullCachePixels!.Length == scratch!.Length)
+        {
+            Buffer.BlockCopy(_fullCachePixels, 0, scratch, 0, scratch.Length);
+            CacheHits++;
+            return new VideoFrame(options.SourceRectWidth, options.SourceRectHeight, scratch);
+        }
+
+        var rendered = _compositor.Render(scene, resolver, flashFrame, options, socialBarFrame, socialBarTop, scratch: scratch, tickerFrame: tickerFrame, timings: timings);
+        CacheRenders++;
+        if (useCache)
+        {
+            var pixels = rendered.BgraPixels;
+            if (_fullCachePixels == null || _fullCachePixels.Length != pixels.Length)
+                _fullCachePixels = new byte[pixels.Length];
+            // PRE-burn / PRE-recycle: the caller burns the counter and recycles this
+            // scratch after RenderScene returns — the cache keeps a clean copy, and the
+            // burn on the next hit writes to a FRESH scratch copy, never the cache.
+            Buffer.BlockCopy(pixels, 0, _fullCachePixels, 0, pixels.Length);
+            _lastFullSignature = signature;
+            _fullCacheValid = true;
+        }
+        else
+        {
+            _fullCacheValid = false; // size changed — never reuse a wrong-size buffer
+        }
+        return rendered;
+    }
+
+    /// <summary>The pump's scene dump (webcam-cadence unit, 2026-10-16): one header line
+    /// plus one line per element, in z-order, carrying the shape two takes must be
+    /// compared by — index, name, kind, source type, visibility, rect in master pixels,
+    /// opacity, clip. <paramref name="split"/> is the SceneGraph split point (-1 when no
+    /// graph is wired: the full-render path). The 10:03 vs 12:01 regression
+    /// (29–34ms → 143–155ms at "the same scene shape") could not be compared because the
+    /// log recorded no scene at all; this is that record.</summary>
+    internal static string[] FormatSceneDump(Scene scene, int split)
+    {
+        var lines = new List<string>
+        {
+            $"FramePump scene dump: '{scene.Name}' elements={scene.Elements.Count}"
+                + (split >= 0 ? $" split={split}" : "")
+        };
+        for (var i = 0; i < scene.Elements.Count; i++)
+        {
+            var e = scene.Elements[i];
+            var source = e is Source s
+                ? $" type={s.Type}{(s.IsBackground ? " background" : "")}"
+                : "";
+            lines.Add($"  [{i}] {e.Name} kind={e.Kind}{source}"
+                + $" vis={(e.IsVisible ? 1 : 0)} rect={e.X:F0},{e.Y:F0} {e.Width:F0}x{e.Height:F0}"
+                + $" op={e.Opacity:F2} clip={e.ClipShape}");
+        }
+        return lines.ToArray();
+    }
+
+    /// <summary>Hash the complete set of inputs the compositor's FULL render consumes:
+    /// the crop/output dimensions, the social bar, and — in element order, mirroring
+    /// <c>SceneCompositor.Render</c>'s iteration — every element's layout/visual fields
+    /// plus the frame each one resolves (through the SAME resolver seam the render will
+    /// use). A changed frame (new capture, new webcam Epoch, new chat raster) changes the
+    /// hash → re-composite; an unchanged one reuses the cache. Buffer-array identity +
+    /// Epoch + CropBounds is the compositor's own paste-key shape — producers hand out
+    /// fresh immutable arrays, or recycled-ring arrays whose monotonic Epoch
+    /// distinguishes generations (the capture take-11 fix), so address-identity alone is
+    /// never trusted to key recycled content.</summary>
+    private static ulong BuildFullRenderSignature(
+        Scene scene, CompositorOptions options, VideoFrame? socialBarFrame, int socialBarTop,
+        VideoFrame? tickerFrame,
+        VideoFrame? flashFrame,
+        Func<SceneElement, VideoFrame?> resolver)
+    {
+        var h = 14695981039346656037UL; // FNV-1a offset basis
+        h = Mix(h, (ulong)options.SourceRectX);
+        h = Mix(h, (ulong)options.SourceRectY);
+        h = Mix(h, (ulong)options.SourceRectWidth);
+        h = Mix(h, (ulong)options.SourceRectHeight);
+        h = Mix(h, (ulong)options.OutputWidth);
+        h = Mix(h, (ulong)options.OutputHeight);
+        h = Mix(h, (ulong)socialBarTop);
+        if (socialBarFrame != null) h = MixFrame(h, socialBarFrame);
+        else h = Mix(h, 0xFFFFFFFFFFFFFFFFUL);
+        if (tickerFrame != null) h = MixFrame(h, tickerFrame);
+        else h = Mix(h, 0xFFFFFFFFFFFFFFFFUL);
+        // BrandFlashPresenter recycles one buffer and bumps Epoch every read, so this
+        // invalidates the cache on every tick of a credit — a cached frame would freeze
+        // the fade and pin a stale spot.
+        if (flashFrame != null) h = MixFrame(h, flashFrame);
+        else h = Mix(h, 0xFFFFFFFFFFFFFFFFUL);
+
+        var backdropResolved = false;
+        foreach (var element in scene.Elements)
+        {
+            h = Mix(h, (ulong)System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode(element));
+            h = Mix(h, element.IsVisible ? 1UL : 0UL);
+            h = MixDouble(h, element.X);
+            h = MixDouble(h, element.Y);
+            h = MixDouble(h, element.Width);
+            h = MixDouble(h, element.Height);
+            h = MixDouble(h, element.Opacity);
+            h = Mix(h, (ulong)element.ClipShape);
+            h = Mix(h, element.IsMirrored ? 1UL : 0UL);
+            h = Mix(h, (ulong)element.BorderWidth);
+            h = MixDouble(h, element.BorderOpacity);
+            if (element.TryGetBorderColor(out var bcR, out var bcG, out var bcB))
+                h = Mix(h, (ulong)((bcR << 16) | (bcG << 8) | bcB));
+            else
+                h = Mix(h, 0UL);
+
+            // Mirror the compositor's per-element frame resolution EXACTLY, so the hash
+            // reacts to the same frames a render uses and never to a frame a render
+            // ignores (a false-positive change only wastes one render; a false NEGATIVE
+            // would serve stale bytes — that is what this mirror prevents).
+            VideoFrame? frame = null;
+            if (element is Source { IsBackground: true })
+            {
+                h = Mix(h, 1UL); // the live backdrop — first visible one is resolved, once
+                if (element.IsVisible && !backdropResolved)
+                {
+                    frame = resolver(element);
+                    backdropResolved = true;
+                }
+            }
+            else if (element is Source { Type: SourceType.TextOverlay })
+            {
+                h = Mix(h, 2UL); // skipped kind — never resolved by the compositor
+            }
+            else if (element is Source { Type: SourceType.Background })
+            {
+                h = Mix(h, 3UL); // background image — resolved even when invisible (Render does)
+                frame = resolver(element);
+            }
+            else
+            {
+                h = Mix(h, 4UL); // regular layer — resolved only when visible
+                if (element.IsVisible) frame = resolver(element);
+            }
+            if (frame != null) h = MixFrame(h, frame);
+            else h = Mix(h, 0UL);
+        }
+        return h;
+    }
+
+    private static ulong Mix(ulong h, ulong v) => (h ^ v) * 0x9E3779B97F4A7C15UL;
+
+    private static ulong MixDouble(ulong h, double v)
+        => Mix(h, unchecked((ulong)BitConverter.DoubleToInt64Bits(v)));
+
+    private static ulong MixFrame(ulong h, VideoFrame frame)
+    {
+        h = Mix(h, (ulong)System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode(frame.BgraPixels));
+        h = Mix(h, (ulong)frame.Epoch);
+        h = Mix(h, (ulong)frame.Width);
+        h = Mix(h, (ulong)frame.Height);
+        if (frame.CropBounds is { } cb)
+        {
+            h = Mix(h, (ulong)cb.X);
+            h = Mix(h, (ulong)cb.Y);
+            h = Mix(h, (ulong)cb.W);
+            h = Mix(h, (ulong)cb.H);
+        }
+        else
+        {
+            h = Mix(h, 0xFFFFFFFFFFFFFFFFUL);
+        }
+        return h;
+    }
+
+    /// <summary>2026-09-12 half-speed-render probe: the pump only produces ~27fps
+    /// (render ~35ms vs the 16.7ms deadline), and rawvideo muxes at the DECLARED fps,
+    /// so every take muxes at ~half its wall length (the truncation complaint). This
+    /// names WHICH compositor path ate the slow frame so the fix targets the real
+    /// stage. Records only when a frame takes ≥20ms (or carries the previous detail).</summary>
+    private void ProbeRender(string path, Scene scene, int split, long totalMs, int bakeMs)
+    {
+        if (totalMs < 20 && _renderDetail.Length == 0) return;
+        var dynamics = 0;
+        foreach (var e in scene.Elements)
+            if (e.Kind == ElementKind.Dynamic) dynamics++;
+        _renderDetail = $"render={path} split={split} elements={scene.Elements.Count} dynamic={dynamics}" +
+                        (bakeMs > 0 ? $" bakeMs={bakeMs}" : "") + $" totalMs={totalMs}";
+    }
+
+    // Dot-matrix digits (5×7, one row per raster line, '1' = lit) burned into the
+    // bottom-right of every composite. Basic OCR-safe shapes, sized so the strip is
+    // a 36×8 white box in the corner of a 1920×1080 frame — readable with a zoomed
+    // player, invisible at normal size.
+    private static readonly string[][] DigitGlyphs =
+    {
+        new[] { "01110","10001","10001","10001","10001","10001","01110" }, // 0
+        new[] { "00100","01100","00100","00100","00100","00100","01110" }, // 1
+        new[] { "01110","10001","00001","00010","00100","01000","11111" }, // 2
+        new[] { "11111","00001","00010","00110","00001","10001","01110" }, // 3
+        new[] { "00010","00110","01010","10010","11111","00010","00010" }, // 4
+        new[] { "11111","10000","11110","00001","00001","10001","01110" }, // 5
+        new[] { "01110","10001","10000","11110","10001","10001","01110" }, // 6
+        new[] { "11111","00001","00010","00100","01000","01000","01000" }, // 7
+        new[] { "01110","10001","10001","01110","10001","10001","01110" }, // 8
+        new[] { "01110","10001","10001","01111","00001","10001","01110" }, // 9
+    };
+
+    private static void BurnFrameIndex(byte[] bgra, int width, int height, long index)
+    {
+        const int digitW = 5, digitH = 7, gap = 1, margin = 2, digitCount = 6;
+        var stripW = digitCount * (digitW + gap) - gap;
+        var left = width - margin - stripW;
+        var top = height - margin - digitH;
+
+        // Solid white box under the digits — the underlying scene can be anything.
+        for (var y = top; y < top + digitH; y++)
+            for (var x = left; x < left + stripW; x++)
+            {
+                var i = (y * width + x) * 4;
+                bgra[i] = 255;
+                bgra[i + 1] = 255;
+                bgra[i + 2] = 255;
+            }
+
+        var text = index.ToString("D6");
+        for (var d = 0; d < digitCount; d++)
+        {
+            var glyph = DigitGlyphs[text[d] - '0'];
+            for (var row = 0; row < digitH; row++)
+                for (var col = 0; col < digitW; col++)
+                {
+                    if (glyph[row][col] != '1') continue;
+                    var i = ((top + row) * width + (left + d * (digitW + gap) + col)) * 4;
+                    bgra[i] = 0;
+                    bgra[i + 1] = 0;
+                    bgra[i + 2] = 0;
+                }
+        }
+    }
+
     private void OnProcessFailed(object? sender, string message)
     {
         _log?.Invoke($"FramePump: encoder process failed: {message}");